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Journal of Ceramic Science and Technology 3/2011
Vol. 2, No. 3 · July 2011
Effect of Mechanical Milling and Sintering Parameters on the Mechanical Properties of SiC-ZrO2
L. Anggraini, R. Yamamoto, H. Fujiwara, K. Ameyama
Pages 139-146 · DOI: 10.4416/JCST2011-00017
Silicon carbide with 50 mass% zirconia ceramic matrix composites were processed by mechanical milling (MM) followed by spark plasma sintering (SPS). By controlling the parameters of MM and SPS, an ultra-fine ZrO2 grain was homogeneously dispersed on the surface of a fine SiC powder, forming a network microstructure. The mechanical properties and the densification behavior of the SiC-ZrO2 composites were investigated. The effects of the milling time on the microstructure and on the mechanical properties of the composite are discussed. The results indicate that the composite mechanically milled …
2.75Yb-TZP Ceramics with High Strength and Aging Resistance
F. Kern
Pages 147-154 · DOI: 10.4416/JCST2011-00020
Tetragonal zirconia polycrystals (TZP) ceramics for biomedical applications such as hip, knee or dental implants require good mechanical properties (hardness, toughness and strength) as well as low-temperature degradation (LTD) resistance. State-of-the-art Y-TZP and Ce-TZP do, however, suffer from deficiencies with regard to one of these aspects.
Shifting to other rare earth stabilizers may help solve this problem. 2.75Yb-TZP powder doped with 0.5 vol% alumina was produced from pyrogenic nanopowder via the nitrate route. Samples were produced by means of hot pressing at 1200 – 1400 °C for 1 h …
In this paper, we report on the electrical and thermal properties of predominantly single-phase Ti3AlC2 ceramics (96.7 wt%) as a function of temperature. The results show that Ti3AlC2 is a good electrical and thermal conductor at high temperature. From 300 to 1173 K, the electrical resistivity of Ti3AlC2 increases linearly from 3.4 × 10-5 to which indicates that Ti3AlC2 ceramic is a metallic conductor. In the 473 to 1473 K temperature range, the coefficient of thermal expansion of Ti3AlC2 yields an average value of 9.3 × 10-6 K-1, which is comparable with the coefficients of Ti2AlC and Ti3SiC2 …
Statistical Optimization of the Binder Mixing Ratio for Fabricating Reliable Ceramic Raschig Rings
A. Salem, Y. Beygi Khosrowshahi, S. Aghahosseini
Pages 159-168 · DOI: 10.4416/JCST2011-00013
Several types of ceramic Raschig rings have been developed for extreme chemical and waste treatment processes. The compressive strength and reliability of ceramic Raschig rings are basically affected by the mixing ratio of the materials used and the quality control of the shaping process. To optimize the above-mentioned properties, various experiments have been conducted. In the present investigation polyvinyl alcohol, carboxymethyl cellulose and Arabic gum were selected and used in an experimental design algorithm. Different amounts of binders were added to a typical kaolin under conditions s …
Synthesis Conditions of Cobalt Aluminate Nano-Sized Powder
Sh. Salem, S.H. Jazayeri, F. Bondioli, A. Allahverdi, M. Shirvani
Pages 169-178 · DOI: 10.4416/JCST2011-00015
The effect of the conditions applied for the synthesis of cobalt aluminate powder on the thermal behaviour of a typical transparent frit was investigated. The nano-sized cobalt aluminate spinels were prepared with the combustion method. The powders were synthesized at a pH of 2.5, 7.0, 10.5 and a fuel ratio of 0.56 and 0.75 using cobalt and aluminium nitrates and glycine as fuel. The obtained gels were calcined at 800 and 1000 °C. 2 wt% calcined powders were added to an industrial transparent frit and the thermal behaviour of the modified glazes was studied by means of hot stage microscopy (HS …
J. Mucha, A. Chuchmała, D. Hreniak, A. Jeżowski, W. Strek
Pages 179-182 · DOI: 10.4416/JCST2011-00014
Thermal conductivity in transparent YAG nanoceramic was measured with the LTHP method in the temperature range 4 – 300 K. It was found that the thermal conductivity of nanoceramics with an average grains size of 16 nm was much lower compared to YAG crystal and polycrystalline ceramics composed of micro-size grains. The results were discussed in terms of the Kapitza resistance model. At about 200 K, Kapitza resistance becomes negative, which indicates a connection with apparent negative thermal conductivity.
Porous TiO2-Y2O3 Ceramics with Specific Infrared-Optical Properties
G. Steinborn, G. Tzschichholz, J. Guenster, M.H. Keller, J. Manara
Pages 183-190 · DOI: 10.4416/JCST2011-00011
The infrared-optical properties and particularly the emissivity of sintered ceramics depend on the material's bulk properties and structural properties such as porosity, pore size distribution and pore diameter. The infrared-optical properties can be varied across a wide range by specifically selecting the material's bulk and structural properties. A major concern of the present study is the development of a ceramic coating material with a total emissivity below 0.2 at a temperature of 800 °C. For this purpose, various samples of a TiO2-Y2O3 (TY) ceramic composite were produced with different …
