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Volume 67 (2015)

List of Contents

Volume 67, Issue 1

  • The effect of cobalt substitution with manganese on the physicochemical properties of NaxCo1-yMnyO2
  • Baster D., Molenda J.
  • Strony: 4-8
  • This work presents a high-temperature method of synthesis of a new cathode material for Na-ion batteries. The material was obtained by substitution of cobalt with manganese in NaxCoO2. The crystal structure and temperature dependence of electrical conductivity of Na0.7Co0.7Mn0.3O2 were investigated. The obtained powder was applied as cathode materials in Na/Na+/NaxCo0.7Mn0.3O2-type cells. Cyclic voltammetry, specific capacity of a cathode material, reversibility and stability during charge-discharge cycles measurements were carried out to characterize electrochemical properties of the cells. The highest discharge capacity of Na/Na+/NaxCo0.7Mn0.3O2 cell was about 104 mAh·g-1 with C/35 current rate. The monotonous voltage changes were recorded in the range of 2.5-3.4 V. The Na0.7Co0.7Mn0.3O2-cathode material showed stability being in contact with electrolyte (1M solution of NaClO4 in carbon propylene) in the temperature range from -30 °C to 150 °C.

    Abstract | PDF (PL) | Szczegóły…
  • Colour properties of pigments based on YMnO3
  • Burkovičová A., Dohnalová Ż, Šulcová P.
  • Strony: 9-14
  • Inorganic pigments of the YMnx(CuSn)1-xOδ (CuSn) and YMnx(NiSn)1-xOδ (NiSn) type, where x = 0.9, 0.5, 0.1, were prepared by wet mechanical activation. Influence of composition and calcination temperature on the colour properties, particle size distribution and phase purity was examined. The pigments were applied into a ceramic glaze and organic matrix. With the calcination temperature increasing from 1000 °C to 1200 °C and with the decreasing content of Mn, the colour of the pigment powders changed from black to dark green in case of CuSn and from black to dark brown in case of NiSn. Particle size distributions (PSD) of the prepared powders varied in the interval suitable for pigment applications. A complete solid solution (hexagonal YMnO3) was obtained only in the case of YMn0.9(CuSn)0.1Oδ. The effect of mineralizers (AlF3, Na3AlF6, H3BO3, Na2CO3) on the colour properties and phase composition was also investigated. The prepared powders were compared with the industrially produced pigments.

    Abstract | PDF (EN) | Szczegóły…
  • Synthesis and characterization of MNd2W2O10 (M = Ni, Cu, Co, Zn) as new ceramic pigments
  • Machalíková V., Bělina P., Šulcová P.
  • Strony: 15-20
  • New compounds based on tungstate were synthesized as environmentally friendly inorganic pigments for ceramic glazes. The pigments have been prepared by means of the solid state reaction. The intermediate compounds MWO4 were synthesized using two methods of preparation: solid state reaction and precipitation. This work is focused on mixed d-electron metal and neodymium (III) tungstate. The optimum conditions for synthesis of intermediate products MWO4 (M = Ni, Zn, Co, Cu), Nd2WO6 and final products MNd2W2O10 were determined by TG/DTA analysis of starting mixtures. The thermal stability of MNd2W2O10 (M = Ni, Zn, Co, Cu) was also determined by TG/DTA methods and by a heating microscope with automatic image analysis. Subsequent research was focused on the influence of d-electron metal tungstates on the colour properties of the MNd2W2O10 pigments. All samples were found in interesting colour hues that were obtained for Ni – green-yellow and for Zn – light violet, Cu – yellow and Co – blue.

    Abstract | PDF (EN) | Szczegóły…
  • High alumina material with reduced sintering temperature, modified with cerium dioxide
  • Dziubak C.
  • Strony: 21-26
  • Cerium dioxide is mostly known as a polishing material and as a catalyst of chemical processes because of strong oxidizing properties of Ce4+ ions. A few papers describe possibilities of using cerium dioxide to modify alumina containing materials. In order to verify currently available information, research was done on sinterability of kaolin and aluminium oxide with an addition of various amounts of cerium dioxide. The physical-mechanical properties of the resultant materials were determined. The sintering temperature of the obtained products was lower than in case of the unmodified materials while maintaining application parameters. This paper presents the results concerning density, porosity, and flexural strength, which were interpreted according to the phase composition and microstructure quality, being a consequence of CeO2 content and sintering temperature. The dependence of final properties of the studied materials on the cerium dioxide precursor was shown. An attempt was undertaken to explain an impact of ceria on alumina material.

    Abstract | PDF (PL) | Szczegóły…
  • Tetragonal zirconia in the 3Y-TZP/Al2O3 system as a solid electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFC)
  • Obal K., Brylewski T., Adamczyk A., Pędzich Z., Rękas M.
  • Strony: 27-36
  • The presented work describes a procedure used to obtain tetragonal zirconia in the 3Y-TZP/Al2O3 system and a study of its physicochemical properties, focusing on its potential application as a solid electrolyte in the intermediate-temperature solid oxide fuel cells (IT-SOFCs). A 3-YSZ powder was obtained from the Y2O3-ZrO2 solid solution of the tetragonal structure containing 3 mol.% Y2O3 by means of the co-precipitation-calcination method. After impregnation of the powder with an aluminum nitrite solution followed by pressing and 2 h sintering at 1773 K in air, a number of 3Y-TZP/Al2O3 materials were obtained, containing 0.35 mol.%, 0.5 mol.% and 0.75 mol.% Al2O3. Physicochemical properties of these polycrystalline materials were investigated using XRD, SEM-EDS, and EIS. As a result of structural and microstructural changes induced by replacing the single-phase 3Y-TZP material with the 3Y-TZP/Al2O3 system containing a small contribution of the monoclinic phase in addition to the tetragonal phase, a significant improvement in the electrical conductivity across grain boundaries was observed at temperatures below 873 K, with an associated slight decrease in the conductivity of the grain interior.

    Abstract | PDF (PL) | Szczegóły…
  • Reinforcing effects of Al4B2O9 whiskers on alumina abrasive composites
  • Herman D., Bobryk E., Walkowiak W.
  • Strony: 37-42
  • A concept of glass-crystalline binder microstructure, reinforced with Al4B2O9 whiskers, intended to bond abrasive grains of microcrystalline alumina into an abrasive composite was presented. The consequence of generating the randomly oriented whiskers within glass-crystalline bonding bridges comprises launching additional mechanisms that absorb energy during cracking. The tensile strength of such composites increased by 32.27% compared to the composites with the glass-crystalline binder composed of the fine-crystalline gahnite phase. The obtainment of the required level of strength in such systems, especially of high porosity, can thus be made by creating the appropriate microstructure of binders in a single, continuous process of heat treatment of the composites.

    Abstract | PDF (PL) | Szczegóły…
  • Fracture mechanics of Y2O3 ceramics
  • Boniecki M., Jach K., Librant Z., Wesołowski W., Węglarz H., Gizowska M., Perkowski K., Witek A., Witosławska I.
  • Strony: 43-47
  • The paper presents mechanical properties of Y2O3 ceramics determined at room temperature and at 800 °C. Measurements of bending strength σc, fracture toughness KIc and subcritical crack growth were carried out as a function of particle size in a range of 6-44 µm. KIc values were determined by the three-point bending test of notched beams. The Weibull parameters of strength distribution were determined. Parameters of subcritical crack growth were obtained on the basis of tests in which bending strength of the samples was measured as a function of stress rate.

    Abstract | PDF (PL) | Szczegóły…
  • The application of Raman spectroscopy to the characterization of sol-gel deposited BST FILMS on stainless steel substrates
  • Lisińska-Czekaj A., Orkisz T., Orkisz J., Czekaj D.
  • Strony: 48-55
  • In the present study, thin films of Ba0.6Sr0.4TiO3 (BST60/40) solid solution modified with 1, 3 and 5 mol.% MgO were prepared by the sol-gel-type deposition method. A multilayer spin–coating approach was utilized for the Ba0.6Sr0.4TiO3 – MgO thin film deposition on stainless steel substrates. Raman spectroscopy investigation of the MgO-doped Ba0.6Sr0.4TiO3 thin films grown on stainless steel substrates were performed within the wavenumber range k = 40-1070 cm-1. The measured Raman spectra were fitted using the Lorentzian peak type to determine positions of multiple overlapping peaks. It has been found that the dominant features in Raman spectra of BST60/40 – MgO thin films are as follows: a broad peak centered at k ≈ 210 cm-1, an asymmetric broad peak around k ≈ 520 cm-1, and a broad peak at around k ≈ 750 cm-1. The observed peaks are typical for the tetragonal structure. The middle frequency band can probably be assigned to vibrations of the TiO6 octahedra.

    Abstract | PDF (PL) | Szczegóły…
  • Determination of subcritical crack propagation parameters for ZrO2 sinters using constant stress rate test
  • Lach R., Dudek A., Pędzich Z.
  • Strony: 56-61
  • Oxide materials have a tendency to crack under stress values lower than expected from KIc values determined in standard tests. This phenomenon is called subcritical crack growth. It is related to slow expansion of flaws existed in the material, which results from chemical interactions, occurring at a tip of the growing crack. Molecules of water, that are present in the crack tip, attach to atoms located in the surface and reduce the surface energy, thereby reducing the amount of energy required to failure. Subcritical crack test methods are labour-intensive. Crack propagation with a speed of 10-10 m/s means that a daily increase of crack length is about 1 micrometer. The paper presents the method of determining the crack propagation speed using biaxial bending tests performed at different stress rates. This is called the constant stress rate test. In this method it is not necessary to measure directly the crack length, but the information on the subcritical cracking results from the performed strength tests. Attempts were made for two groups of tetragonal zirconia samples, which matched different sintering conditions. The first was sintered for 6 hours at 1400 °C, while the second one for 2 hours at 1500 °C. The sintering at the higher temperature resulted in larger grain growth than at 1400°C.

    Abstract | PDF (PL) | Szczegóły…
  • Comparative studies of vibratory crushing process performed in jaw crushers
  • Sidor J., Mazur M.
  • Strony: 62-66
  • Research of the crushing process of limestone and diabase was carried out in two vibrating jaw crushers: one of kinematic and one of inertial actuation of the oscillating motion of jaws, and in a typical jaw crusher. The grain size of the crushed material was in the range of 0-40 mm. Limestone came from “Czatkowice” Mine in Krzeszowice while diabase from “Bear Mountain” Mine in Tenczynek. The best results concerning degrees of fragmentation: i50 and i90, outputs of grain classes of 0-1.0 mm and 0-2.0 mm, and technological efficiency were obtained in the vibratory crushers.

    Abstract | PDF (PL) | Szczegóły…
  • Effects of halloysite on the CaO-SiO2-H2O system in hydrothermal conditions
  • Owsiak Z., Sołtys A.
  • Strony: 67-70
  • This paper presents the results of the studies carried out in the model systems and concerning the tobermorite synthesis with an addition of halloysite. Quartz sand and quicklime were the main raw material constituents. The mixtures of these constituents and 5%, 10% or 30% of halloysite in the form of homogenous slurries underwent hydrothermal treatment for 12 h at 180 °C. The resultant composites were analysed for their phase composition using XRD, DTA and TG methods. The microstructure was examined using SEM. Tobermorite was the principle reaction product. When 30% halloysite was added to the mixture containing CaO and SiO2, the formation of katoite was found.

    Abstract | PDF (PL) | Szczegóły…
  • Application of dolomite refractories in selected steel ladles
  • Sułkowski M., Goławski C., Obszyńska L., Kielski A.
  • Strony: 71-76
  • Dolomite refractories based on the dolomite clinker received from domestic deposits of dolomite, produced by ArcelorMittal Refractories, are characterized by high operational stability in the production of silicon killed steel. This was possible by addition of carbonaceous material and modification of the organic binder. To obtain good performance results, a complete design solution of the ladle lining has been developed, including the insulating layer and sealing mixes. In the developed technological solution, emissions of harmful substances into the atmosphere were reduced.

    Abstract | PDF (PL) | Szczegóły…
  • Working conditions of seepage barriers for hydrotechnical structures
  • Bojarski A., Opaliński P., Przecherski P.
  • Strony: 77-80
  • Safety of hydrotechnical structures depends mainly on technical condition of seepage barriers of the embankment, foundation and abutments. According to a variety of hydrotechnical structures and different foundations there are many types of seepage barriers. Main requirements for designing and construction of the seepage barriers in embankment dams and levees are presented in the paper. There are two main groups of seepage barriers: upstream face lining and inclined or central cores. Due to the necessity of joining foundation treatment and embankment, the type and technology have to be chosen concerning many different factors. In designing seepage barriers, the knowledge is important on technology of sealing and information on the diversification of thickness and depth of the barrier, conducting works on construction in stages and working at variable water levels, different widths of core, and different foundation types, making constructions in fully and partially saturated zones, a long life–span, and resistance to atmosphere conditions and biological actions. Those factors have to be taken into consideration to design the level of crest of the seepage barrier and crest of the embankment, technical solution of joints between two technologies and joints with concrete structures. Due to complex conditions and consequences of malfunctioning of seepage barriers, maintenance during construction and operation is needed.

    Abstract | PDF (PL) | Szczegóły…
  • Innovative instrumental measurement systems for quasi-3D monitoring of seepage and erosion processes and deformations in dams and dikes
  • Radzicki K.
  • Strony: 81-87
  • The development of measurement methods and the development of the methodology for their measurements and analysis, including the development of automatic systems for controlling the condition of built structures, make it possible to use more efficient and effective measurement solutions. This also applies to the hydro-engineering construction, in particular damming hydraulic structures, such as dams and flood protection dikes. For these structures, minimisation of the risk of failure and/or repairs is a very important issue. The article presents the concept of quasi-spatial monitoring of seepage and erosion processes and deformations using instrumental sensors, especially including innovative linear sensors. They enable a quality change in the monitoring of hydraulic structures into linear measurements and, with an appropriately designed system, into quasi-spatial ones.

    Abstract | PDF (PL) | Szczegóły…
  • Application of local correlations for determination of geotechnical parameters of stone ground within the precinct of Czorsztyn Lake
  • Apostoł S.
  • Strony: 88-92
  • A methodology is proposed for determining the strength parameters of stone ground and coarse-grained one, containing stone fractions. The methodology uses basic terraintial and laboratory examinations, including measurements of particle size distribution, volumetric density and moisture absorption, and applies local correlations together with the rule of “comparable experiments”. Three soils were taken from a region of the precinct of Czorsztyn Lake and subjected to the methodology. The proposed method allows determining necessary parameters of the stone ground when the methods described in related standards fail.

    Abstract | PDF (PL) | Szczegóły…
  • Advanced technologies and modern building ceramic products
  • Jaroszewicz M., Klimm J.
  • Strony: 95-100
  • During past few decades, ceramic bricks passed technological evolution in speed and scale previously unimaginable. Without exaggeration we can say that since the sixties of the last century until present day, innovation in production technology of ceramic bricks and masonry techniques is much greater than all previous achievements in this field, reaching 800 years in Poland and much longer in the world. It should be emphasized also, that this development nowadays becomes faster, which is particularly visible in the last decade.

    Modern brick produced on industrial scale is a result of technological processes carefully designed and perfectly executed, starting from modern raw material extraction through the heap building process and ending in the fully automated and computerized manufacturing process. New generation bricks are invariably produced from natural raw materials but also with attention to energy saving and environmental protection.

    Among modern building ceramic products, ceramic bricks with high thermal insulation performance, that are dedicated to energy-efficient housing in single layer wall technology with no need of additional thermal insulation, deserve special attention. Durability and healthy microclimate inside buildings are main advantages of this technology. Modern bricks are getting bigger; their structure becomes more sophisticated which allows keeping a relatively small mass, and, what is very important, the bricks can be still produced in high compressive strength in classes 10 and 15. They are strong, durable and robust.  Some of their types can be used in seismically active areas. The idea of modern thermal brick concerns not only the internal structure, number of voids or their shape, but also the level of porosity and firing techniques. Recently introduced ceramic products are also filled with natural insulating materials such as mineral wool or perlite. Beyond the thermal bricks, modern bricks of superior airborne sound insulation deserve also to attention. These are optimally large, heavy bricks of the AKU type. What is worth of special emphasis - one variant of such acoustic brick also meets the thermal requirements and plays absolutely a unique, dual role in constructions. The modern building ceramics products offer great opportunities for design freedom, efficient and robust buildings as well as comfortable and healthy living conditions. They are willingly used by architects, contractors and end users.

    Abstract | PDF (PL) | Szczegóły…

List of Contents

Volume 67, Issue 2

  • Alumina foams manufactured by the gel-casting method designed for polymer infiltration
  • Potoczek M., Ligoda J., Śliwa R.E.
  • Strony: 104-108
  • Ceramic-polymer composites are characterized by the unique spatial structure of interpenetrating skeletons of polymer and ceramic phases. Infiltration of a liquid polymer into a porous ceramic material is the way of producing these type of composites. In this paper, alumina (α-Al2O3) samples of a foam structure produced by the gelcasting of foams process were used. The advantage of ceramic foams manufactured by the gelcasting method is higher mechanical strength when compared to those produced by the most popular technique known as the polymeric sponge method. Before the infiltration process, the alumina samples were characterized in terms of total and open porosity; sizes of macropores and interconnections between macropores were also determined. Compressive strength and permeability of the alumina foams were studied. The alumina foams were infiltrated by three-functional epoxy resins in order to obtain composite materials of low density having enhanced mechanical strengths and reduced flammability. These materials have potential application in aerospace industry.

    Abstract | PDF (PL) | Szczegóły…
  • The reaction mechanism of calcium hexa-aluminate formation in the CaAl4O7-Al2O3 system
  • Jonas S., Pięta A., Bućko M.M., Czyżewska A., Krupa G.
  • Strony: 109-112
  • This work presents the results of research over a course of formation of calcium hexa-aluminate CaAl12O19 (CA6) during firing a mixture of calcium dialuminate CaAl4O7 (CA2) and Al2O3 powders. The CA6-forming reaction is important in evolution of the microstructure of refractory materials made from these compounds. Calcium hexa-aluminate, which forms at the interface of coarse Al2O3 grains and surrounding matrix CA2, increases porosity, and introduces local changes of thermal expansion. Knowledge of the CA6-forming reaction is necessary in designing technologies of the foregoing materials. In the study, a degree of conversion as a function of temperature and time of firing the materials in the system were determined by X-ray diffractometry and the Rietveld method. The evolution of microstructure was analysed by using SEM images and EDS spectra. The kinetic temperature threshold and kinetic equation of the reaction were formulated, basing on the collected experimental data. It has been found that the slowest elementary step limiting its course is growth of CA6 nuclei, forming at the CA2-Al2O3 interface.

    Abstract | PDF (PL) | Szczegóły…
  • The material constants of anisotropic Al2O3-hBN composites.
  • Piekarczyk W., Rutkowski P., Górny G.
  • Strony: 113-116
  • This paper presents the results of determination of elastic and material constants of hot pressed aluminium oxide matrix composites containing from 0% to 30% of hexagonal boron nitride. The measurements of ultrasonic waves velocities with required polarization allowed determining all elastic and material constants for the tested samples both isotropic and anisotropic due to the presence of the hexagonal phase. This gave a possibility to verify and supplement formulas used for determining all the elastic constants of ceramic materials with hexagonal anisotropy. For alumina composite with 30% hBN, the following material constants were determined: Young's moduli E║ = 93,5 GPa and E┴ = 181,3 GPa, moduli of rigidity G║ = 52,9 GPa and G┴ = 74,4 GPa, in a direction parallel and perpendicular to the pressing, respectively; Poisson ratios had values of μ12 = 0,219; μ13 = 0,162; μ31 = 0,084. Regarding anisotropic materials fabricated by pressing and belonging to the hexagonal system, there is an option of determining some material constants using the formulas usually used for isotropic materials.

    Abstract | PDF (PL) | Szczegóły…
  • The investigation of the vibratory dry milling of silicon carbide
  • Sidor J., Tomach P.
  • Strony: 117-120
  • Studies were carried out in a vibratory laboratory mill with a low frequency of vibration (14 Hz) and periodic action. The silicon carbide milling process was performed in the air environment in a steel chamber and steel balls were grinding mediums. In the investigation, two types of SiC powders (marked with symbols A and B) of different grain sizes and amounts of impurities were used. Grain sizes of the SiC-A and SiC-B feeds were 0-10 mm and 0-1,6 mm, respectively. For each type of SiC, different technological objectives of the grinding process were accepted. The main goal of the work was to obtaine dry milled powders of SiC-A and SiC-B with grain sizes of d50 < 15 μm and d50 < 3 μm (a BET surface area over 3 m2/g), respectively. Both of the technological objectives have been achieved. In the experiment, there were obtained the milled powders of SiC-A with d50 = 10.4-14.6 μm and SiC-B with d50 in the range of 2 - 3 μm and a BET specific surface area of 3,2-4,0 m2/g. The results confirm the complete usefulness of vibratory mills for grinding SiC.

    Abstract | PDF (PL) | Szczegóły…
  • Centrifugal crushers in processes of fine crushing
  • Sidor J.
  • Strony: 121-126
  • The centrifugal crushers are the impact crushers with a rotor of vertical axis. These crushers are used in the processes of impact crushing, especially medium, fine and very fine, crushing of grained minerals and manufactured materials (clinker, metallurgical slag and others). They are also used in the outward processing of aggregates. A special implementations of these crushers are used as mills for milling, particularly selective, mainly the manufacture of products with a narrow grain class. These crushers are characterized by high technological capabilities, including suitability for shredding highly abrasive materials. Hence the large increase in interest in them of the users and manufacturers. Paper presents elements of the theory of impact shredding in the centrifugal crushers, classifications, descriptions of construction, operation and technical characteristics of the most common crusher. There are also presented their technological capabilities in the processes of very fine crushing of raw materials and grained ceramic products.

    Abstract | PDF (PL) | Szczegóły…
  • Influence of the direct crystallization process on bioactivity of silicate-phosphate glasses from the NaCaPO4-SiO2 system
  • Wajda A., Bułat K., Sitarz M.
  • Strony: 127-131
  • Silicate-phosphate glasses from the NaCaPO4-SiO2 system are well-known bioactive materials, which are capable of forming direct bonds with living tissue. However, their brittleness limits the use of implants made of them. One of the ways to improve the mechanical properties of the glasses is to introduce proper additives (e.g. AI3+) to their chemical composition. Another one is to carry out their partial crystallization that allows obtaining glass-crystalline materials. This process needs to be highly controlled because the appearance and growth of the crystalline phase may result in loss of the bioactivity.

    The subject of this paper concerns silicate-phosphate glasses from the NaCaPO4-SiO2 and NaCaPO4-SiO2-AlPO4 systems. Parameters of the direct crystallization process were adjusted on the basis of thermal analysis measurements (DTA) performed on selected glasses. The XRD method was used to study the structure of obtained glass-crystalline materials. In order to verify their bioactivity, the in vitro tests were done in simulated body fluid and the samples were analyzed on a scanning electron microscope (SEM+EDX) and Raman spectroscopy.

    The obtained results suggest that the properly controlled devitrification of the tested bioglasses may lead to the production of bioactive glass-crystalline materials.

    Abstract | PDF (PL) | Szczegóły…
  • Carbide ceramics in lightweight armour applications
  • Cegła M., Habaj W., Podgórzak P.
  • Strony: 132-136
  • Carbide ceramics have been successfully used for ballistic armour applications protecting against armour piercing projectiles. A combination of high hardness and low density makes ceramics a good substitute of traditional steel armours. Properties of two ceramic armour materials: silicon carbide (SiC) and boron carbide (B4C) are being described. Finally the authors present results of ballistic tests of ceramic-based multi-layered armours systems against modern pistol ammunition with armour piercing capabilities.

    Abstract | PDF (PL) | Szczegóły…
  • Porosity and optical properties of TiO2-SiO2 with organic groups
  • Iwan A., Hreniak A., Malinowski M.
  • Strony: 137-142
  • In this paper two TiO2-SiO2 powders with organic groups were prepared by the sol-gel technique by application of two various silane precursors (VTMS and MAPTS) and titanium one (TIPO). The particle size of the obtained TiO2-SiO2 powders (called in the paper as TiO2-SiO2-VTMS and TiO2-SiO2-MAPTS) was investigated by the dynamic light scattering (DLS) method. The influence of type of silicon precursors on such selected properties as absorption in the UV-vis range and porosity of TiO2-SiO2 was analyzed.

    Abstract | PDF (PL) | Szczegóły…
  • Effect of Si source (Si3N4 / SiO2) on synthesis and properties of SrSi2O2N2 oxynitride phosphor doped with Eu2+ and Mn2+.
  • Pawlik T., Michalik D., Barzowska J., Szczodrowski K., Zieliński K., Górecka N,
  • Strony: 143-148
  • Oxynitride compounds doped with europium ions are the subject of intensive research. The reason is that such compounds can be used as phosphors in production of white LEDs due to their high chemical and thermal stability. Together with the relevant optical properties this type of compounds can be more promising than solutions based on cerium doped yttrium aluminium garnet. The aim of this study was to determinate the effect of SiO2 addition on the phase composition and morphology of SrSi2O2N2 phosphor powder doped by divalent rare earth ions. The synthesis of powders was carried out for 2 h at 1450 ºC under the flow of nitrogen. The study of the powders morphology and phase composition was performed by SEM/LM and XRD, respectively; the optical properties, i.e., emission and excitation spectra were also examined.

    Abstract | PDF (PL) | Szczegóły…
  • Influence of magnesia precursor form and sintering time on properties of partially stabilized zirconia of the PSZ type
  • Grabowy M., Bućko M.M.
  • Strony: 149-157
  • Zirconium dioxide is recently one of the most frequently used material for structural, functional and biomedical applications. Preparation of a solid solution by introducing into the ZrO2 structure approx. 8 mol% of CaO or MgO in combination with specific heat treatment of the solution (aging) result in a material with good mechanical properties called as partially stabilized zirconia (PSZ). Since the sintering of PSZs occurs simultaneously with the formation of the solid solution, the morphology of starting powders has a significant influence on the phase composition, the microstructure and the mechanical properties. Similarly, sintering and aging conditions have strong effects on PSZ’s properties. Materials investigated in this work were prepared by sintering of mixtures composed of baddeleyite powder and either magnesium oxide or fully stabilized zirconia solid solution with a maximum MgO content one. Time of sintering at 1640 °C was changed from 1 h to 5 h. The phase compositions, microstructure and mechanical properties of the obtained materials were studied. The obtained results allowed determining the correlation among the properties, form of the MgO precursor and sintering time.

    Abstract | PDF (PL) | Szczegóły…
  • Rheology of soil binder dispersions
  • Izak P., Wójcik Ł, Słowikowski D.
  • Strony: 158-163
  • A technique of injection of soil binder suspensions is the most frequently used technology of hydro engineering works. The technique is still developed in a direction of automation of the process and improvement of the properties of soil binders suspensions. In the article, properties of dispersions containing soil and cement are studied and reported taking into account viewpoints of both the rheology and the application in hydro-geological industry.

    Abstract | PDF (PL) | Szczegóły…
  • Effects of waste materials on thermal properties of black glass
  • Kosmal M., Reben M., Pichniarczyk P.
  • Strony: 164-170
  • The paper presents a study on the impact of waste materials in the form of CRT glass panel cullet and basalt on thermal and electrical properties of black glass. Based on differential thermal analysis (DTA) and research with the usage of a gradient furnace, the influence of chemical composition of the waste materials on physico-chemical changes occurring during the heating of glass has been established. In addition, the process of melting could has been optimized. The type of crystalline phases and microstructure of heat-treated glasses were identified using the X-ray diffraction phase analysis (XRD) and scanning microscopy (SEM/EDS), respectively. It has been found that the waste materials can be used to produce black glass having a coefficient of thermal expansion in the range of 7.5·10-6 °C-1 to 8.5·10-6 °C-1.

    Abstract | PDF (PL) | Szczegóły…
  • Study of the structure, phase and chemical compositions of Bi1−xNdxFeO3 ceramics
  • Dzik J., Czekaj D.
  • Strony: 171-176
  • In the present research Bi1−xNdxFeO3 (x = 0.6-1) ceramics were synthesized by the standard solid-state reaction method from a mixture of oxides, followed by free sintering at a temperature T = 1000 ºC. Ceramic powder was obtained from simple oxides Bi2O3, Fe2O3 and Nd2O3 using classical technology. A thermogravimetric analysis of the stoichiometric mixture of starting oxides was carried out, allowing the determination of synthesis and sintering temperatures. The influence of Nd-doping on the chemical composition and microstructure of Bi1−xNdxFeO3 ceramics was studied by scanning electron microscopy and energy dispersion spectroscopy. It has been found that an increase in Nd content (x) caused a decrease in the average size of ceramic grains. The crystal structure was determined by X-ray diffraction.

    Abstract | PDF (PL) | Szczegóły…
  • Photocatalytic properties of CdS/TiO2 nanocomposites
  • Trenczek-Zając A., Banaś J., Świerczek K., Zazakowny K., Radecka M.
  • Strony: 177-181
  • CdS/TiO2 nanocomposites were prepared as a mixture of commercially available TiO2 P25 nanopowder with CdS nanopowder which has been synthesised with the use of the precipitation method. Based on the measurements it has been found that the specific surface area (SSA) changed in a wide range from 49.5 m2·g-1 up to 145.4 m2·g-1 for TiO2 and CdS, respectively. Particle size distributions obtained by dynamic light scattering (DLS) and transmission electron microscopy (TEM) images revealed agglomeration. X-ray diffraction patterns (XRD) suggested crystallization of CdS as a mixture of two phases: cubic and hexagonal. In the case of nanocomposites, spectral dependence of diffused reflectance spectra exhibited the presence of fundamental absorption edges being characteristic for both CdS and TiO2. Photocatalytic activity of CdS/TiO2 in the UV-vis light was tested with the use of methyl orange (MO). Based on the photocatalytic experiment it is concluded that the photocatalytic activity of the TiO2/CdS mixture has been significantly improved in comparison with pure TiO2 or CdS nanopowders.

    Abstract | PDF (PL) | Szczegóły…
  • Oxyfluoride Borosilicate Glasses Doped With Gd2O3
  • Kasprzyk M., Środa M., Naspiński P.
  • Strony: 182-186
  • Oxyfluoride glasses, based on borosilicate matrix, constitute an interesting material for optoelectronic applications due to their ability to form transparent glass-ceramic materials with a nancrystalline, low phonon phase. Based on the previously performed research on the formation of LaF3 in the glass the possibility of obtaining gadolinium based fluorine phase in a glassy matrix was studied. In this experiment, a series of glass in the SiO2-B2O3-Na2O-NaF-Gd2O3-BaF2 system was obtained. The glasses were analysed using DTA/DSC, XRD, FT-IR, and transmittance methods to determine the influence of chemical compound on thermal stability, ceramization process and formation of fluoride crystalline phases.

    Abstract | PDF (PL) | Szczegóły…
  • Mechanical and optical properties of glass coated with zirconia by the sol-gel method
  • Drajewicz M., Jadach R., Długoń E., Reben M., Sitarz M.
  • Strony: 187-190
  • Unsatisfied mechanical strength frequently limits the usage of glasses. Its improvement can be attained by coating the glass surface with a thin layer of material with better mechanical properties than the glass. Silicate-sodium-calcium glass coated with zirconia was the object of this study. The sol-gel method has been used to produce a coating of zirconia. Vickers’ hardness and Young’s modulus were determined for the coatings. Transmittance of the coated glasses was determined by UV/VIS spectroscopy. The applied sol-gel method was useful to improve properties of glass surfaces.

    Abstract | PDF (PL) | Szczegóły…
  • Prehistoric pottery from the Skrzypkowo 13 site: a comparative study using AAS, XRD and γ-ray spectroscopy
  • Kowalski Ł, Adamczak K.
  • Strony: 191-200
  • This article presents the results of a comparative study performed on 50 prehistoric potsherds from the Skrzypkowo 13 site (Dobrzyń Land). All the materials were classified to the Neolithic and the early Bronze Age, that are dated on Dobrzyń Land in a period 4200-1500 cal. B.C. The potsherds were grinded and the chemical and phase composition of the resultant powder was identified by atomic absorption spectrometry (AAS) and X-ray diffraction (XRD), respectively. Moreover, the γ-ray detection of the resultant powder was performed using γ-ray spectroscopy. The data set was statistically elaborated using multidimensional analyses such as principal component analysis (PCA) and discriminant analysis (DA). It permits to follow association rules within individual sets, such as cultural units and technological groups. It has been found that the grouping of the analyzed fragments proceeded in the space of variables that can be correlated with mica minerals or feldspars, marls, endogenous iron compounds and dark minerals. The obtained results have permitted to put some hypotheses on the manufacturing behaviour of prehistoric potters concerning vessel production patterns, circulating of so called exclusive vessels of the Early Bronze Age societies or episodic nature of the prehistoric settlement activity on the Skrzypkowo site that was the most readable in a case of Subneolithic groups.

    Abstract | PDF (PL) | Szczegóły…
  • Abstracts of 14th Conference on Composites and Ceramic Materials – Technology, Application and Testing, Białowieża, June 1st-3rd 2015
  • Strony: 201-234
  • Komunikat

List of Contents

Volume 67, Issue 3

  • Thermophysical properties of Ag-C composites
  • Homa M., Sobczak N., Gazda A., Siewiorek A., Kudyba A., Pietrzak K., Frydman K., Wójcik-Grzybek D., Strojny-Nędza A.
  • Strony: 248-256
  • The work presents the results of preliminary studies of Ag-C type materials obtained by the powder metallurgy method and doped by using carbon of different form, comprising carbon nanopowder, carbon nanotubes, and graphene oxide. Basing on SEM microstructural studies and DSC, DIL, and LFA measurements, it has been stated that the applied manufacturing procedure did not guarantee the satisfied distribution of the carbon phase within the metal matrix. A deagglomeration method of the carbon phase is to be developed to improve homogeneity of the Ag-C materials.

    Abstract | PDF (PL) | Szczegóły…
  • Investigation of the mechanism of dehydration of hydrated calcium zirconium aluminate
  • Madej D., Szczerba J.
  • Strony: 257-261
  • In this paper, the results of investigation of the phase composition and microstructure of hydrated calcium zirconium aluminate paste are presented. The paste was first cured at room temperature, and then additionally heat treated at a temperature located within a temperature range of 100-900°C. The XRD, FT-IR and SEM/EDS techniques were used for characterization of the hydrated and dehydrated samples. The dehydration process of hexagonal calcium aluminate hydrates C-A-H (C ≡ CaO, A ≡ Al2O3, H ≡ H2O) proceeded through a transitory stage of the C3AH6 formation due to evaporation of physically bonded water, and partial removal of chemically bonded one; as a result, anhydrous calcium aluminates, C5A3, C12A7 and C3A were formed. Additionally, both an unknown ternary compound belonging the CaO-Al2O3-ZrO2 system, forming dehydrated rings on the unhydrated core of Ca7ZrAl6O18 grains, and calcium zirconate, CaZrO3, were identified.

    Abstract | PDF (PL) | Szczegóły…
  • Dolomite clinker with reduced content of impurities for refractory fired materials
  • Niesyt M., Wala T.
  • Strony: 262-267
  • Two kinds of clinkers have been obtained from Devonian dolomite of the Brudzowice deposit: sintered clinker produced by a two-stage sintering method, and fused one. The latter shows better hydration resistance in comparison to the sintered clinker due to its higher apparent density and more coarse-grained structure. Fired samples obtained from the fused clinker show higher refractoriness under load, better dimensional stability after sintering and similar cold crushing strength in comparison to the samples prepared from the sintered clinker. Refractoriness under load measured under a reducing atmosphere is much higher than measured under an oxidizing atmosphere. Hydration resistance of fired samples depends on their open porosity. The incorporation of magnesia clinkers contributes to a notable improvement of this parameter.

    Abstract | PDF (PL) | Szczegóły…
  • Ceramic foam materials obtained by the gelcasting method using nitrogen-free organic monomers
  • Lipowska B., Śliwa A., Czechowska K., Wala T., Psiuk B.
  • Strony: 268-273
  • The aim of the undertaken work was to obtain an Al2O3-based foam ceramic product during the manufacture of which toxic acrylamides were replaced by a set of water-soluble monomers with no nitrogen atoms in their particles: 2-hydroxyethyl acrylate and poly(ethylene glycol) diacrylate. The type and amount of additives (deflocculant and surface active agent) as well as the alumina content in a suspension that enable obtaining a stable, maximally aerated foam were determined The polymerization of foamed suspensions was carried out in the nitrogen atmosphere in order to avoid the phenomenon of oxygen inhibition. The obtained half-finished products were fired at 1500-1700 C. After firing, the products were characterised by determining their basic physical properties and microstructure. The obtained results indicate a possibility of using less toxic monomers to produce foam ceramic products by the gelcasting method.

    Abstract | PDF (PL) | Szczegóły…
  • Foam ceramic-carbon filters for the foundry industry – starting from a concept to mass production
  • Asłanowicz M., Ościłowski A., Lipowska B.
  • Strony: 274-278
  • Together with the Institute of Ceramics and Building Materials, Refractory Materials Division in Gliwice, the Foundry Research Institute in Cracow and the Institute for Chemical Processing of Coal in Zabrze Ferro-Term Sp. z o.o. has developed a technology of manufacturing innovative ceramic-carbon filters for the foundry industry. The newly developed filters should allow exceeding the operational parameters of currently used ZrO2 or SiC filters. It is one of the basic conditions that will enable to start with mass production. The second condition is to achieve a level of production process mechanization enabling its high efficiency. Ferro-Term Sp. z o.o., basing on the technology of manufacturing foam ceramic-carbon filters, proceeded to prepare a design and implement of a prototypical mechanized production line. In the paper an initial construction design of the line is described.

    Abstract | PDF (PL) | Szczegóły…
  • The usability of asbestos containing wastes  in the manufacture of sintered ceramic building materials
  • Kusiorowski R., Zaremba T., Piotrowski J.
  • Strony: 279-285
  • The paper reports the results of studies on the usage of cement-asbestos waste as an additive to ceramic masses designated for the sintered building ceramics. In these studies, pre-calcined at 1200 °C cement-asbestos waste was used. Prepared ceramic masses contained up to 10 wt.% of the calcined asbestos materials. After forming, the green compacts were sintered at temperatures of 1100-1200 °C. The basic ceramic product properties such as linear shrinkage, water absorption, open porosity, apparent density, compressive strength as well as freeze resistance and presence of soluble salts were examined. The scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal analysis methods (DTA/TG) were applied for the characterization of the used raw materials and obtained clinker ceramics. The results of these investigations show that the asbestos-containing materials can be used as a potential secondary raw material in the manufacture of sintered ceramic building materials.

    Abstract | PDF (PL) | Szczegóły…
  • Influence of nitrate salts on properties of building ceramics
  • Wons W., Wyczyńska K.
  • Strony: 286-290
  • The main factor causing corrosion of ceramic building materials is the formation process of efflorescence. It devastates not only aesthetics of ceramic products, but also contributes to gradual degradation of the products. The influence of sulphate salts is well described because of their common occurrence in the raw materials used for production of ceramic materials. There is little information available concerning the corrosion caused by nitrate salts although they are appearing increasingly frequent in the vicinity of ceramic materials because of human activity related to the use of nitrogen fertilizers or animal husbandry. The article compares the destructive influence of the nitrate salt on ceramic materials to magnesium sulphate. The experimental part comprised cycles of wetting of porous ceramic materials in salt solutions and drying, and then the main parameters of the materials were measured and analyzed. It has been shown that the nitrate salts had the destructive effect on the ceramic materials, but of slightly different nature when compared to magnesium sulphate.

    Abstract | PDF (PL) | Szczegóły…
  • Comparative studies on the microwave and conventional drying of refractory castable
  • Majchrowicz I., Czechowski J.
  • Strony: 291-297
  • The microwave method has aroused a lot of interest in recent years due to its potential application in the processes of ceramic materials drying. In contrast to conventional drying, in which heat is provided from the outside through the material surface, in microwave drying, microwaves penetrate the inside of the material, heating its whole volume. The use of microwaves in the drying process has many advantages, such as: high heating rate, elimination of external heat sources, reduced number of faulty products, and low energy consumption per unit. The aim of the work was to conduct comparative studies on the microwave and conventional drying of corundum refractory castable. Samples of low-cement refractory castables were prepared with and without an addition of microsilica. The samples were cured in a climatic chamber for 48 h at 20 ºC at humidity reaching 95%. Next, some samples were dried in a laboratory electric drier for 24 h, and the other part of the samples were dried in a laboratory microwave drier. Physical properties of the samples (apparent density, open porosity) and their compression strength were determined. A thermal analysis of the castables was also conducted, their phase composition was determined by the X-ray diffraction method and their microstructure was subjected to observation in a scanning electron microscope. The obtained results were compared and discussed.

    Abstract | PDF (PL) | Szczegóły…
  • Modification of the microstructure of bottom casting assembly materials to increase their resistance to the erosive and corrosive action of steel
  • Pochwała T., Barański J., Śliwa A., Wala T.
  • Strony: 298-303
  • The work presents a concept and possibilities resulting from application of the impregnation process for bottom casting assembly materials. Impregnation of aluminosilicate materials with castable suspensions of alumina powder or alumina and silicon oxide powders causes favourable microstructural changes, comprising the reduction of open porosity, the reduction of average pore diameter and pore diameter distribution median as well as an increase in the share of pores having diameters below 1 µm at the cost of larger pores. The impregnation of bottom casting assembly materials results in an increase in their resistance to the erosive and corrosive action of steel flowing through a system of bottom casting, and in a decrease of the amount of non-metallic inclusions in the cast steel. The developed solution was tested under industrial conditions at ZWK Celsa Huta Ostrowiec Sp. z o.o.

    Abstract | PDF (PL) | Szczegóły…
  • Comparative studies on dolomite-carbon materials made from sintered and fused clinkers
  • Sułkowski M., Onyszkiewicz A., Goławski C.
  • Strony: 304-308
  • The use of fused magnesite raw materials is currently a standard in refractory magnesia-graphite materials used in modern metallurgical processes. The limitation is the use of low-alkalinity slags, in which case it is better to apply MgO-CaO-C materials. The addition of fused grains of dolomite is aimed at reducing the rate of the corrosion process, in particular the mechanism of big grains dissolution. Comparative studies were conducted in a laboratory induction furnace. The degree of corrosion progression in samples of different types of dolomite clinker was determined, and the microstructure of the slag contact layer was examined. The use of fused clinker limited corrosion by reducing the rate of material loss in the slag contact area which provides a reason for developing a new type of basic material to be used in the metallurgical ladle slag zone.

    Abstract | PDF (PL) | Szczegóły…
  • Modelling of wear rate for basic refractory materials in a laboratory rotary kiln
  • Zelik W., Świerszcz R., Pedryc B.
  • Strony: 309-313
  • Processes of refractory materials’ wear are a reference point for the development and proper selection of materials used in the working linings of major metallurgical units. For many years, attempts have been undertaken to model physical and chemical processes which at least slightly would allow forecasting the quantitative wear of refractory materials in the assumed modelling conditions. In the paper, an attempt has been undertaken to mathematically describe the process of basic materials’ corrosion in a laboratory rotary kiln for testing materials’ resistance to liquid slag. The process was run by the dynamic method. The dimensional analysis was applied in the model. Owing to a series of tests, the coefficients of the derived criterial equations were determined as well as a correlation between refractory material loss and time. Tests were conducted for three types of slag having different CaO/SiO2 ratios, for three different angular velocities of the rotating drum.

    Abstract | PDF (PL) | Szczegóły…
  • Conductometric investigations for the effect of waste aluminosilicate on the early hydration of alumina cement depending on temperaturę
  • Nowacka M., Pacewska B.
  • Strony: 314-318
  • Hydration process of calcium aluminate cement is strictly temperature-dependent. The curing temperature is deciding factor, mainly, about the kind of hydrates formed. It is known that at low and ambient temperature the formation of metastable calcium aluminate hydrates is favoured, while at higher temperature hydrogarnet and gibbsite are dominated. On the other hand the curing temperature decides also about the kinetics of calcium aluminate cement hydration and causes the anomalous setting behaviour.

    The aim of this work was to evaluate the impact of mineral addition in calcium aluminate cement matrix at different curing temperatures. The study included the investigation of the waste aluminosilicate effect on the course of setting and hardening of the cement paste (Al2O3 > 70%, w/c = 0.5) depending on the curing temperature and the amount of the addition using a conductivity method. The used in situ technique consists the simultaneous measurement of electrical conductivity and internal temperature of cement paste from the first minutes after adding water. Moreover, the microstructure was examined by the thermal analysis method and scanning electron microscopy.

    Based on the results, it has been found that the temperature of hydration determines the kinetics and reactions during the setting and hardening of calcium aluminate cement paste, both, with and without the mineral addition as well as decides about the influence of the aluminosilicate. Regardless of the curing temperature and the presence of addition, the changing of process kinetics is carried out throughout the duration of the induction period, but depending on the temperature, the waste aluminosilicate acts as a retarder or accelerator of the massive precipitation of hydrates. Furthermore, regardless of the temperature, it has been shown that the introduction of the addition causes rise of the thermal effects in the first minutes, but also reduces the maximum of the internal temperature of paste. The phase composition studies reported the higher the temperature effect than the presence of waste aluminosilicate.

    Hydration process of calcium aluminate cement is strictly temperature-dependent. The curing temperature is deciding factor, mainly, about the kind of hydrates formed. It is known that at low and ambient temperature the formation of metastable calcium aluminate hydrates is favoured, while at higher temperature hydrogarnet and gibbsite are dominated. On the other hand the curing temperature decides also about the kinetics of calcium aluminate cement hydration and causes the anomalous setting behaviour.

    The aim of this work was to evaluate the impact of mineral addition in calcium aluminate cement matrix at different curing temperatures. The study included the investigation of the waste aluminosilicate effect on the course of setting and hardening of the cement paste (Al2O3 > 70%, w/c = 0.5) depending on the curing temperature and the amount of the addition using a conductivity method. The used in situ technique consists the simultaneous measurement of electrical conductivity and internal temperature of cement paste from the first minutes after adding water. Moreover, the microstructure was examined by the thermal analysis method and scanning electron microscopy.

    Based on the results, it has been found that the temperature of hydration determines the kinetics and reactions during the setting and hardening of calcium aluminate cement paste, both, with and without the mineral addition as well as decides about the influence of the aluminosilicate. Regardless of the curing temperature and the presence of addition, the changing of process kinetics is carried out throughout the duration of the induction period, but depending on the temperature, the waste aluminosilicate acts as a retarder or accelerator of the massive precipitation of hydrates. Furthermore, regardless of the temperature, it has been shown that the introduction of the addition causes rise of the thermal effects in the first minutes, but also reduces the maximum of the internal temperature of paste. The phase composition studies reported the higher the temperature effect than the presence of waste aluminosilicate.

    Abstract | PDF (PL) | Szczegóły…
  • Which factors influence the bulk density and open porosity testing results for dense shaped refractory materials?
  • Dahlem E., Clasen S., Dannert C.
  • Strony: 319-323
  • This paper highlights the efforts that were undertaken within the framework of the EU FP7 “ReStaR” research project for the determination of testing parameters and conditions (factors) influencing the bulk density (BD) and open porosity (oPo) testing results of dense shaped refractory materials. Besides the generation of precision data, it is necessary to understand which instructions in the standard EN 993-1 for dense shaped refractories are sensitive for diverging testing results and are therefore to be considered as significant factors influencing those results. Screening factorial designs were used to identify those significant factors in bulk density and open porosity testing of dense shaped refractories. For this material, up to fifteen possible factors were identified and set to two different levels each. Accordingly, 16-trial runs, taking into account the possible factors, were carried out in laboratories with this type of refractory. The analysis of variance method was used to analyse the testing results. For dense shaped refractories, results showed that the place of extraction of the samples (internal or external part of the brick) and the immersion liquid (water/paraffin) are factors that significantly affect the results of BD and oPo testing. On the other hand, the sponging material, the time of evacuation and the soaking time under water at ambient conditions were found not to influence the results of BD and oPo testing. A second design of experiment, which contained the four most significant factors, was studied for this refractory material in four different laboratories. Hereby estimations of the repeatability and of the reproducibility of the testing standards for BD and oPo across different laboratories were obtained. For the EN 993-1 standard tested on an alumina dense shaped refractory (not reacting with water as immersion liquid), a reproducibility of 0.07 g/cm3 and a repeatability of 0.04 g/cm3 were obtained for the BD and a reproducibility of 1.6 vol% and a repeatability of 1.2 vol% were obtained for the oPo.

    Abstract | PDF (EN) | Szczegóły…
  • An analysis of factors influencing the determination of refractory materials’ compression strength
  • Gerle A., Czechowski J., Podwórny J., Dahlem E.
  • Strony: 324-332
  • Cold crushing strength (CCS) testing is one of the basic tests conducted in order to characterize a refractory product. Compression strength is frequently a condition that must be fulfilled by a product to be technically accepted, and the result obtained in the test strongly depends on measuring conditions. For this reason, the applied measuring procedures must guarantee the repeatability and reproducibility of the obtained results. The standards in force specify CCS testing methods depending on the density of a product (dense and insulating products) and its form (shaped and unshaped products). These standards specify the requirements to be fulfilled by the dimensions of CCS test samples, their perpendicularity and parallelism, the requirements to be met by the machine used for CCS testing, the number of test samples as well as the sample loading rate during the test. However, not all standards sufficiently define all the requirements. Imprecise testing procedures and difficult to test inhomogeneous materials, such as refractories are, make it difficult to obtain repeatable and reproducible results and to compare them by different laboratories.

    The presented investigations are an initial part of international project ReStaR, aimed at specifying the factors which significantly influence among others the result of CCS testing. The investigations were based on experimental design methods and variance analysis, which allowed minimizing the number of experiments necessary to identify factors that have a considerable influence on CCS testing of refractory materials: dense shaped, insulating and unshaped products. It has been proved that the obtained result of CCS testing is significantly influenced by the quality of sample preparation and sample dimensions. In the case of insulating and unshaped products, an important factor turned out to be the rate of loading the sample during the test. In the case of all the types of materials subjected to testing, the use of a cardboard washer had a negative impact on the test result, reducing the value of strength and the repeatability of the obtained results.

    Abstract | PDF (EN) | Szczegóły…
  • Current situation in the production and consumption of refractory materials in the Czech Republic and Slovakia
  • Franek T.
  • Strony: 333-336
  • In recent years the branch of refractory materials in the Czech Republic and Slovakia has undergone considerable changes. After the global crisis in the years 2008-2009, the consumption of refractory materials was reduced and their production dropped considerably. In the production assortment the manufacture of chamotte and basic shapes has been greatly reduced. The consumption of refractory materials produced in the Czech Republic and Slovakia has been considerably shifted from metallurgical industry to other branches of industry, such as foundry industry, cement and lime production, glass manufacturing and power engineering.

    Abstract | PDF (PL) | Szczegóły…
  • Refractory materials industry in Poland and worldwide – condition and directions of development
  • Czechowski J.
  • Strony: 337-341
  • The role of refractory materials industry in the development of industries that use these materials has been emphasised and illustrated with an example of steel industry. The scale of refractory materials production worldwide, in China, European Union and Poland has been discussed. Changes in the structure of production in China in recent years have been emphasised. Refractory materials’ export from China has been presented. The production and export of refractory materials in European Union and in Poland have been characterised. The situation of raw materials has been addressed while emphasizing the role of China as the main source of primary refractory raw materials on the global market and the significance of recycling has been highlighted. In this context the attention has been drawn to the fact that natural resources are depleting and graphite and bauxite have been included in the list of critical raw materials for European Union. Factors determining the role of refractory materials and research directions have been discussed.

    Abstract | PDF (PL) | Szczegóły…
  • The use of perlite in the synthesis of zeolite A
  • Król M., Misiaszek A., Mozgawa W.
  • Strony: 342-346
  • This paper presents the results of research on the synthesis of zeolite material using a waste fraction originated from the production of expanded perlite. A process was carried out to obtain the structure of zeolite A at a relatively low temperature, using the hydrothermal method. Influence of the composition of a reaction system (expressed as Si/Al and Na/Si mole ratios) and the temperature on the amount and nature of resulting reaction products was analyzed. The optimal conditions, under which it is possible to obtain the structure of zeolite A, were determined, basing on analysis of the phase composition,.

    Abstract | PDF (PL) | Szczegóły…
  • Abstracts of 1st Polish-Korean Joint Workshop on Advanced Ceramics, Zakopane, September 19th, 2015
  • Strony: 347-352
  • Komunikat
  • Abstracts of SINTERCER Workshop on Nanomaterials Sintering with the Use of SPS and HP-HT Techniques, and SINTERCER Seminar on Influence of Advanced Techniques of Sintering on Microstructure and Physico-mechanical Properties of Nanomaterials, Zakopane, September 17th, 2015
  • Strony: 353-359
  • Komunikat
  • Koblenz University of Applied Science, Department of Materials Engineering, Glass and Ceramics playing a key role in the science and education network for the refractory industry
  • Strony: 360-362
  • Biuletyn

List of Contents

Volume 67, Issue 4

  • Properties of Ca-α-Sialon:Eu2+ phosphors prepared via carbothermal reduction and nitridation of zeolites
  • Pawlik T., Michalik D., Sopicka-Lizer M., Rzychoń T., Lisiecki R.
  • Strony: 372-377
  • Materials based on Ca-α-sialons doped with Eu+2 can be an alternative for phosphors in white diodes WLED. However, manufacturing Ca-α-sialon powders with a designed chemical composition of the solid solution is a difficult task, so a lot of research is devoted to their synthesis. In the present work a commercial high purity zeolite powder Z 500 (Zeolyst) with an appropriate Al:Si ratio for a phosphor composition of Eu0.05Ca0.8Si9.6Al2.4O0.8N15.2 was used together with the appropriate amount of carbon black. Eu2O3 was used as a source of the phosphor activator Eu+2. The synthesis was carried out in a temperature range of 1550-1650 ºC under an atmosphere of nitrogen flow. The resulting material was characterized by the optical emission in a range of 530-680 nm with a maximum at 570-581nm, when the excitation wavelength of 450 nm has been applied. These parameters allow using it as a phosphor in white LEDs excited by blue light of GaN LEDs.

    Abstract | PDF (PL) | Szczegóły…
  • Fracture toughness of Y2O3 ceramics
  • Boniecki M., Librant Z., Wesołowski W., Gizowska M., Osuchowski M., Perkowski K., Witek A., Witosławska I., Karczmarz M.
  • Strony: 378-382
  • In this study we have measured fracture toughness of yttrium oxide ceramics, which had a mean grain size of approx. 6 μm, by analyzing cracks of stress cracking impressions of a Vickers pyramid. Values of KIc were calculated by means of several formulas that originated from analytical considerations of different authors. The obtained results were in the range of 1.0-1.50 MPa∙m1/2, being smaller than those obtained by the three-point bending method (approx. 1.8 MPam1/2).

    Abstract | PDF (PL) | Szczegóły…
  • Simplifications in determination of material constants by the ultrasound method for anisotropic materials of hexagonal symmetry
  • Piekarczyk W., Kata D.
  • Strony: 383-387
  • The calculation of Young's modulus, shear modulus and Poisson’s ratio for isotropic materials by the ultrasound method is a relatively simple procedure. It is enough to measure the velocity of propagation of longitudinal and transverse ultrasonic waves, and to use the appropriate formulas to calculate the constants. However, a lot of measurements of longitudinal and transverse waves, polarized in appropriate directions are needed for anisotropic materials. A sample should be properly oriented to the axis of symmetry. These measurements are very time-consuming and complicated.

    All material constants for anisotropic composite Al2O3 - hBN and anisotropic porous polycrystalline graphite, which have hexagonal anisotropy, were calculated by ultrasound method in accordance with the complicated procedure appropriate for anisotropic materials. The material constants were also determined in respective directions of the samples, using the simplified method by treating them as the isotropic materials.

    Values of Young’s (E, E) and shear modules (G and G), when determined using the simplified method, differ slightly (no more than 7%) from the values determined from the equations adequate for the anisotropic materials belonging to the hexagonal system. However, the simplified method cannot be used to determine Poisson's ratio values. In the case of Al2O3 composite with the highest content of hBN (30%) Young's modules of 95.0 GPa (E║(3)) and 177.1 GPa (E┴(1)) were calculated by the simplified method, and of 93.5 GPa (E║(33)) and 181.3 GPa (E┴(11)) by the anisotropic methodology.

    Abstract | PDF (PL) | Szczegóły…
  • Investigation of the influence of structural defects on the magneto-optic properties in oxide glasses
  • Golis E.
  • Strony: 388-392
  • The paper presents results of research in tellurite oxide glasses with the addition of rare earth elements. The parameters of glass structure defects were measured by using positron annihilation lifetime spectroscopy (PALS), and all spectra were analysed by the LT9 computer program. The evaluation of the magnetic properties of the investigated materials was based on the determination of the dominant type of magnetic order by measuring the DC magnetic susceptibility. The magneto-optic properties were determined on the basis of Faraday effect measurements and the Verdet constant calculated from the turn angle of the plane of light polarization. The spectroscopic study allows drawing conclusions regarding the defect nature and defect degree of the investigated glasses structure. The number of point defects increases in tellurite glasses with the addition of rare earth ions, and the number of volume defects decreases. There are volume defects in tellurite glasses, and the rare earth ions addition causes an increase of average defect sizes and a simultaneous decrease of the defects amount. These changes correlate with changes in the density of the investigated glasses. The results of magnetic susceptibility measurements indicate the change in the nature of magnetic ordering induced by the addition of rare earth ions. A tendency towards increased values of magnetic susceptibility with the addition of erbium ions is observed in the investigated tellurite glasses. Ordering in glasses remains of the paramagnetic type after the adding erbium ions. The magneto-optic effect is reduced with the increase of the erbium ions addition despite of a slight increase in magnetic susceptibility. An increase in both the amount of point defects and average volume defect sizes, which is indicated by the  PALS measurements, together with a small value of magnetic susceptibility may influence such a behaviour of the magneto-optic effect in this case. The addition of erbium could be too small to increase the magnetic susceptibility sufficiently, and to eliminate the disorder originated from changes in the structure of defects which can deteriorate the magneto-optic properties. The Verdet constant is smaller than in oxide glasses, which contain diamagnetic elements such as lead and bismuth. The obtained Verdet constants reflect the influence of structural changes on the observed properties of glasses, and can provide important indications for the development of new materials with unique magneto-optic properties for applications in optoelectronic devices.

    Abstract | PDF (PL) | Szczegóły…
  • Effect of the support structure on the conversion degree in the low temperature CO oxidation reaction on Au/Al2O3–TiO2 catalysts
  • Rajska M.
  • Strony: 393-399
  • The aim of this study was to determine the effect of the Al2O3-TiO2 support phase composition and the addition of gold on low-temperature catalytic oxidation of CO. In this paper, physicochemical properties of catalyst carriers in the system and related catalysts by gold are reported together with the results of catalytic measurements. The catalyst carriers were prepared with the sol-gel method using Al(C3H7O)3 and Ti(C3H7O)4 alkoxides to obtain the corresponding oxides wherein an Al:Ti molar ratio was 0.75:0.25. The catalysts by gold were prepared by depositing gold in a theoretical loading of Au 2 wt%, using the deposition-precipitation method. To examine the effect of the phase composition on the catalytic activity of the obtained samples, the carrier precursors were calcined at two different temperatures: 500 °C and 1350 °C. This made it possible to obtain the assumed polymorphs of alumina and titanium(IV) (γ-Al2O3, α-Al2O3, anatase and rutile), and then to determine the catalytic properties of the selected phase in the reaction of low temperature oxidation of CO. The prepared samples were characterized by XRD, BET, and SEM. Particle size distributions and catalytic activity were also measured. The highest catalytic activity showed the Au/Al2O3-TiO2 catalyst based on the support calcined at 500 °C, which achieved T90 at 110 °C

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  • Consolidation of aluminium oxide powders using hydrolysis of aluminium nitride
  • Wojciechowski K., Lach R., Bućko M.M.
  • Strony: 400-406
  • Polycrystalline aluminium oxide is one of a basic structural ceramic material which is used in production of components of machines and devices, cutting tools, grinding aids or refractory materials. Green bodies are generally formed by uniaxial pressing, but it is problematic in case of powders having large particle sizes, e.g. in technologies of refractory materials. The aim of the paper was to examine effectiveness of usage of the consolidation process supported by hydrolysis of aluminium nitride (hydrolysis-assisted solidification method) in sintering technology of corundum powders with different morphologies. In this study, two alumina powders of various particle size with an addition of 10 wt% aluminium nitride and water were used. Aluminium hydroxide, which was a product of aluminium nitride hydrolysis, bound together aluminium oxide grains, causing a reduction in porosity and an increase in strength of compacts that were dependent on the alumina particle size, and had a decisive influence on density of sintered bodies.

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  • The structure of components of fly ash with different granulation
  • Wons W., Murzyn P., Kłosek-Wawrzyn E.
  • Strony: 407-412
  • Fly ashes produced by combustion of pulverized hard coal have specific properties that make possible their various applications. These properties include: the spherical grain shape, the high content of aluminosilicate glass, and the chemical composition similar to kaolinite type raw materials. The article presents a detailed description of the structure of components of selected fly ashes. For this purpose, 27Al nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR) together with an analysis of the phase composition by XRD/Rietveld were used. The studied ashes of different graining were taken from different zones of electrostatic precipitators. The research provided information about the structure of ash constituents and showed a number of differences between the ashes. It has been proved that the aluminium in the fly ash glassy phase occurred only in the tetrahedral positions and the amount of glass is greater in finer grains. Moreover, the glass is characterized by greater isomorphic substitutions Si4+↔Al3+ and greater amount of terminal Si-O- bonds.

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  • Effect of blunt notch in specimen on fracture parameters of cement composite
  • Kosior-Kazberuk M., Kazberuk A.
  • Strony: 413-417
  • The study for assessing the influence of notch curvature in a specimen on fracture mechanics parameters, e.g. critical stress intensity factor and fracture energy, was performed on cement mortar as a typical quasi-brittle material. The U-shaped notches with a depth of 30 mm were formed during molding the specimens. The radius of the notch curvature was changed in the range from 0.15 mm to 30.0 mm. The obtained results demonstrated that the notch curvature radius had a significant effect on the level of maximum stress and the parameters describing resistance to cracking of the cement composite. Therefore, the experimental determination of the fracture characteristics requires a strict definition of the test conditions.

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  • Population balance modelling of free grinding
  • Otwinowski H., Zhukov V.P., Zbroński D., Belyakov A.N.
  • Strony: 418-420
  • During free comminution, a material to be ground plays the role of grinding medium simultaneously. The intensity of this process is mainly determined by the content of large particles in the feed that act as the grinding media. Therefore, in a mathematical model of the free comminution, nonlinear kinetics equations must be used which allow describing the influence of the comminuted material on the intensity of grinding. Modelling of the process of autogenous grinding is carried out on the basis of the population balance model. The article presents a stochastic model, in which the breakage function is represented as the product of the probability of particle loading and the probability of breakage of load particle. The parametric identification of the model is carried out on the basis of experimental tests. The proposed model allows calculating the particle size distribution of free comminution products at any time, and also formulating and solving problems of the effective monitoring and the efficient control of the grinding process.

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  • Ferroelectric ceramics - How it is made
  • Ćwikiel E.
  • Strony: 421-425
  • Final properties of ferroelectric ceramics depends on the processing conditions. Major applications of ferroelectric ceramics are presented. Processing steps: preparation of starting materials, synthesis by mixed oxides method, forming, sintering and finishing are described.

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  • The criteria for selection of raw materials for the producing ceramic proppants
  • Dziubak C., Rybicka-Łada J., Taźbierski P.
  • Strony: 426-429
  • During the extraction of shale gas the hydraulic fracturing process is used to produce, maintain or enlarge cracks in rocks with help of fracturing fluids containing filling materials called proppants. The proppant is either natural or artificial aggregate, which due to its function, has specific properties. The most important one include the mechanical resistance to compression and regular spherical shape of particles with a diameter of 0.3-0.7 mm and a relatively low apparent density. A low price is important due to the large demand for proppants. The conditions for the fulfilment of specific requirements of proppants are the right selection of raw materials, which takes into account content their chemical composition and price, and the low-energy and high-performance manufacturing process. This justifies the usage of waste materials in the manufacturing process. From well-known, published methods of proppants producing, a mass granulation and sintering method meets these conditions.

    The article presents the study of properties of ceramic materials, that are a base for proppants, as a function of the type of raw materials used. A final research result is to assess the fulfilment of the assumed quality criteria of the proppants.

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  • Microtructural aspects of friction stir processing of the AZ magnesium alloy with the use of Cr2O3 particles
  • Iwaszko J., Kudła K., Przerada I., Zawada A.
  • Strony: 430-433
  • The study examined the effects of the friction stir processing (FSP) of the surface layer of AZ91 magnesium alloy with the application of Cr2O3 ceramic particles. The microstructural changes resulting from the treatment were assessed both macro- and microscopically, and hardness measurement was performed. FSP was found to have a positive impact on the microstructure and properties of the magnesium alloy. The surface treatment led to an increase in the hardness of the material and to a strong microstructure refinement of the processed layer. In the friction-processed samples, Cr2O3 ceramic particles were observed to be highly dispersed in the surface layer of the material, thus forming a metal-ceramic composite microstructure. Cr2O3 particles were present in both the stirred zone (SZ) and the thermo-mechanically affected zone (TMAZ). A characteristic attribute of the SZ was its high microstructure refinement and the presence of equiaxial grains, whereas in the TMAZ elongated grains distributed along the lines of displacement of the softened material were prevailing. The research has demonstrated that the use of the FSP technology for the processing of the surface layer of magnesium alloys with ceramic particles is a promising solution, which has a considerable application potential.

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  • Technological properties characterization of ceramic slurries based on silicon carbide powder
  • Małek M., Wiśniewski P., Mizera J., Kurzydłowski K.J.
  • Strony: 434-437
  • In this work technological properties of ceramic slurries for ceramic shell moulds fabrication were characterized. The slurries were based on silicon carbide powder and nanocomposite binder with colloidal aluminium oxide particles. For modification of rheological properties of the slurries, three binders were added: poly(vinyl alcohol)l with a molecular weight of 47 000 g/mole and 88% of hydrolysis degree, poly(ethylene glycol) with a molecular weight of 1500 g/mole, and a polyacrylic dispersion. The content of silicon carbide solid phase was 65 wt.%. The ceramic slurries were fabricated in an air-condition lab in a reactor equipped with a mechanical mixer. The total time of experiment was 96 h. The first measurement was performed after 24 hours from beginning of the test in order to use the slurries of better homogenization. Relative viscosity by Zahn Cup 5#, density, pH and adhesion were measured every day during the experiment. The silicon carbide powder was additionally characterized for its microstructure (SEM), grain size and chemical composition. It has been proven that the addition of new binders increased the technological properties of the investigated ceramic slurries which was conducive to their future use in the foundry industry.

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  • Application of utilitarian and sanitary ceramics waste in cement mortars
  • Jura J., Halbiniak J., Ulewicz M.
  • Strony: 438-442
  • Currently, ceramic wastes from the production of ceramic flower pots and covers are not used in any form. Therefore in this paper, the preliminary results of utilization of these wastes directly or in conjunction with waste of ceramics sanitary for the production of ceramic mortars made in accordance with PN-EN196-1 are presented. The chemical composition of the waste materials tested was determined by using X-ray fluorescence. The influence of the ceramics waste addition and the mixture of utilitarian and sanitary ceramics (in a ratio of 50:50), when used as cement or aggregate replacements, on selected properties of cement mortar made using CEM I 42.5 R were investigated. The characteristics of the cement mortar with the addition of ceramic waste of a particle size of less than 0.03 mm were based on microscopic studies (SEM analysis with EDS) and the assessment of mechanical and physical parameters, i.e. the compressive strength and the frost resistance. The results showed that the cement mortar, in which 15% of the cement and 15% of the natural aggregates were replaced by the ceramics waste, had higher (approx. 5.1%) compressive strength when compared to the conventional standardized mortar. A compressive strength of 70.0 MPa, which is similar to the mortar standard one (70.3 MPa) was obtained for the sample where 15% of the cement has been replaced by the mixture of ceramics waste (in ratio of 50/50). Whereas, the cement mortar, in which 15% of the natural aggregate was replaced by a mixture of the utilitarian and sanitary ceramics, showed the lowest compressive strength of 66.0 MPa. After the freeze resistance test (150 cycles of freezing and unfreezing), the largest decrease of compressive strength (over 25%) showed the cement mortar, where the utilitarian ceramics waste was used instead of cement, while the smallest decline of compressive strength of approx. 8% was obtained for the cement mortar, in which 15% of the aggregate has been replaced by a mixture of utilitarian and sanitary waste.

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  • Rheological properties of ceramic slurries based on zrsio4 for ceramic shell moulds preparation
  • Szymańska J., Wiśniewski P., Małek M., Mizera J.
  • Strony: 443-447
  • This research concerns properties of ceramic slurries prepared from ZrSiO4 applied for the “prime coat” fabrication in ceramic shell moulds in the investment casting process. The solid phase content was 75% by weight. Modification of the slurry rheological properties was based on addition of four deflocculants such as DISPEX N-40, DURAMAX, POLIKOL and THS as a 10 wt% water solution in an amount of 0.25 wt% with respect to the powder. The ceramic slurries were prepared in a mechanical mixer with a speed equal to 300 RPM within 3 hours. The morphology and chemical properties of ZrSiO4 powder were characterized by SEM and XRF. The powder grain size distribution was determined by laser diffraction. The rheological properties like dynamic viscosity were studied in an air-conditioned lab at 21 °C. The obtained results for the ZrSiO4 based ceramic slurries indicate that the application of deflocculants can decrease or increase dynamic viscosity significantly, when compared to the slurry containing only water).The addition of deflocculants to ZrSiO4 based ceramic slurries is very useful to modify viscosity of them in industrial conditions.

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  • Studies on receiving ceramic proppants by the spray drying method
  • Wiśniewski P., Małek M., Szymańska J., Zarzycka-Dziedzic D., Mizera J., Kurzydłowski K.J.
  • Strony: 448-453
  • The paper presents exemplary results of research related to green ceramic proppants obtained in a spray dryer, and opportunity of their production on industrial scale. Ceramic proppants are classified as propping agents used in the hydraulic fracturing process applied in the shale gas and shale oil exploitation. This technique is based on the shale rocks fracturing inside a borehole and further injection of a hydraulic fluid containing suspended proppants. The aim of this material is to prop open fractures and facilitate unconventional gas flow. The scope of the conducted studies was production of light ceramic proppants from Polish mineral raw materials by using spray drying. For this purpose, ceramic slurries have been prepared with the addition of deffloculants, and examined to determine their rheological properties. The selected slurries were used for production of green propping agents in the spray dryer. The investigation also included characterization of the proppants according to their density, sphericity and microstructure. Morphology estimation was carried out with the use of light microscopy, scanning electron microscopy (SEM) combined with EDS analysis at micro areas, and also Roentgen tomography. The studies have proved that the obtained materials demonstrate favourable properties enhancing their application in the industrial output for shale gas extraction.

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