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Volume 70 (2018)

List of Contents

Volume 70, Issue 1

  • Preparation and physicochemical properties of xLi2MnO3·(1-x)LiMO2 - high-voltage cathode materials for Li-ion batteries
  • Redel K., Kulka A., Ziąbka M., Molenda J.
  • Strony: 3-12
  • The work presents the description of high temperature solid-state reaction synthesis cathode materials based on Li2MnO3 and 0.9Li2MnO3·0.1LiMn1-yNiyO2 (0.1 ≤ y ≤ 0.9). The crystal structure and phase composition of the synthesized materials were examined by the XRD technique. To characterize the microstructure a scanning electron microscope SEM was used. Changes of the particle size with increase of the nickel content in tested materials were also determined. In order to perform electrochemical measurement, the Li/Li+/Li2MnO3 and Li/Li+/0.9Li2MnO3·0.1LiMn1-yNiyO2 cells were prepared, followed by a cyclic charge and discharge test. Specific capacity and stability were examined during the charge and discharge cycles at a current rate of C/20, C/10 and C/5 in a voltage range of 2.0-4.8 V. The highest discharge capacity was found for the composition 0.9Li2MnO3·0.1LiMn0.1Ni0.9O2. For this material, a reduction of the irreversible capacity decrease during the first charging was also observed.

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  • Unit thermal decomposition time of limestone vs. limestone origin and dimensions of cylindrical samples undergoing calcination
  • Lech R., Szeląg H., Szostak P.
  • Strony: 13-19
  • With today’s requirements for increased productivity imposed by all customers, a good understanding of the limestone calcination process is very important. There are several process variables that are crucial in optimization of the limestone calcination. This paper is addressing the impact of a size of the calcined pieces, and a quality of the limestone (purity and homogeneity) on the unit thermal decomposition time. It is shown that the thermal decomposition rate of various limestones is statistically different depending on the limestone origin, affecting heterogeneity of physicochemical properties of heated samples, and their dimensions. A decrease of unit thermal decomposition time values, scaled with the unit initial sample mass, with increased dimension of a cylindrical sample placed in a cylindrical heating chamber with constant dimensions is also documented in the paper. Moreover, the coefficient of variation of the unit thermal decomposition time of the limestone samples depends on the properties of calcined limestone and the conditions of calcination determined first of all by radiation heat transfer between heating chamber walls and the sample surface, and secondly by carbon dioxide transport from the reaction surface to the heating chamber filled with a gaseous mixture.

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  • Assessment of fracture toughness of ZrB2 based UHTC composites obtained by SPS and HP–HT methods
  • Bączek E., Naughton-Duszova A., Podsiadło M., Dubiel A.
  • Strony: 20-28
  • The effect of the addition of silicon carbide and boron carbide powders on the properties of ZrB2 ceramic composites constituting ultra high temperature ceramics (UHTC) was investigated. Polycrystalline zirconium boride samples, as well as composites with the matrix of this phase with the addition of 2 wt.% and 10 wt.% of SiC and B4C were obtained by pressure-assisted sintering using SPS/FAST (spark plasma sintering / field assisted sintering technology) and HP–HT (high pressure -high temperature) methods. The composites were characterized in terms of phase composition, microstructure, hardness and fracture toughness. It has been stated that they had a high relative density in the range of 97% to 98%. Higher hardness and fracture toughness was observed for composites with the addition of ceramic phase obtained by HP–HT method.

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  • Properties of Dy-doped BiFeO3 ceramics
  • Dzik J., Pikula T. , Wodecka-Duś B., Feliksik K., Szalbot D., Szpara S.
  • Strony: 29-35
  • In the present research Bi1-xAxFeO3 (A = Dy, for x = 0, 0.03, 0.05, 0.07 and 0.1) ceramics was synthesized by the standard solid-state reaction method from the mixture of oxides. Ceramic powder obtained from the simple oxides Bi2O3, Fe2O3 and Dy2O3 using classical technology. The crystallographic structure, microstructure and magnetic properties of the obtained ceramic materials were studied.

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  • The effect of excess Bi2O3 on the synthesis and properties of BiNbO4 ceramics
  • Rerak M.
  • Strony: 36-42
  • BiNbO4 is a ceramic belonging to the family of materials with the scheelite structure. It shows promising ferroelectric properties that can be successfully used in high frequency techniques or microelectronics. In this work, the synthesis conditions were determined and the effect of excess Bi2O3 and sintering temperature on the properties of the BiNbO4 ceramic were described. The test material was prepared by solid phase reaction using a high purity oxide mixture (99.99%). Excess Bi2O3 did not affect the minimum required temperature of synthesis of bismuth nibate powder, however, it affected the phase composition of sinters, their density and microstructure.

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  • Synthesis of Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite-like material by spray pyrolysis method for oxygen separating membranes application
  • Gromada M., Trawczyński J.
  • Strony: 43-49
  • The Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) mixed oxide with perovskite-like structure was synthesised by a spray pyrolysis method. The calcination temperature required to obtain a single phase material was determined by DTA/DTG analysis. Physical and chemical properties of the obtained powder (morphology, texture, phase composition and particle size distribution) were determined. The BSCF powder was granulated in order to improve its compactibility. The green compacts of BSCF material were moulded by combined uniaxial and isostatic pressing. An optimal curve which ensure high density of obtained sinters has been elaborated. The key parameters that determine the suitability of the BSCF material for the oxygen separating membranes forming i.e.: apparent density, open porosity, water absorbability and surface microstructure were determined. The obtained outcomes confirm that the BSCF perovskite powder prepared by the spray pyrolysis method possesses the appropriate properties for manufacturing membranes separating oxygen from air.

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  • Chemical stability of a 3-YSZ-Al2O3 electrolyte in relation to electrode materials for use in the intermediate-temperature solid oxide fuel cells
  • Molin S., Bobruk M., Wyrwa J., Pleśniak J., Brylewski T.
  • Strony: 50-64
  • One of the main features required of materials to be applied as electrolytes in intermediate-temperature solid oxide fuel cells (IT-SOFCs) is their chemical compatibility with electrodes at both operating temperatures and the temperatures at which the cells are manufactured. To verify whether the investigated composite electrolyte with a matrix consisting of partially stabilized zirconia and alumina inclusions of 1 mol% (3-YSZ-Al2O3) can be applied to ensure a sufficiently high long-term operating efficiency of IT-SOFCs, its chemical stability was analyzed via exposure to the La0.6Sr0.4Co0.2Fe0.8O3 (LSCF48) cathode material and NiO, which constitutes the main component of the anode material. After annealing the mixture consisting of the electrolyte and the cathode material at a mass ratio of 1:1 for 5 and 100 hours at 1273 K, the presence of new phases that might affect the electrochemical properties of the electrolyte/cathode junction was observed. Under the anticipated operating conditions of the cell, i.e. at 1073 K, the electrolyte exhibits significantly higher chemical stability in contact with the anode material than when exposed to the cathode one, which can be attributed to the reduced interdiffusion of cations in the 3-YSZ-Al2O3/NiO system.

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  • A review of materials used in middle ear prosthetics
  • Ziąbka M.
  • Strony: 65-85
  • The need to replace or reconstruct ossicles has led to the development of surgical techniques enabling innovative prosthesis implantation. New structural and material possibilities have influenced the design and preparation of prostheses, making it vary in size, shape and the applied material. Nowadays, it is common knowledge that a properly designed material may cause a different, more advantageous postoperative answer. Modifying the chemical composition makes changes to the parameters and functions of mechanical prostheses. In the case of enormous damage to the natural ossicular chain, it is advisable to administer the prostheses made of alloplastic materials, e.g. metal, ceramics, artificial plastics or composites. However, all the materials applied as implants must meet strict requirements. This review describes materials used in middle ear surgery.

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