H. Aydın,
Volume 16, Issue 4 (12-2019)
Abstract
Mullite–zirconia composites were prepared using lanthanum oxide (La2O3) additive which three different mole ratio by the reaction sintering (RS) route of alumina, kaolinite and zircon. Starting materials were planetary milled, shaped into pellets and bars and sintered in the temperature range of 1450–1550 0C with 5 h soaking at peak temperature. In this work, the mullite-zirconia composites were characterized by thermal expansion coefficient, physical, microstructures and mechanical properties. The XRD method were employed for determining the crystalline phase composition of these composites. Microstructure of the composites was examined by SEM. ZrO2 takes part in both the intergranular as well as intragranular positions. However, intragranular zirconias are much smaller compared to intergranular zirconias.
Zahra Rajabimashhadi, Rahim Naghizadeh,
Volume 19, Issue 1 (3-2022)
Abstract
ꞵ-tricalcium phosphate (ꞵ-TCP) and anorthite are the main crystalline components in bone china bodies. The difference in their thermal expansion coefficients causes a decrease in the thermal shock resistance of the body. In this study, anorthite was replaced with bone ash at the bone china body, and the effect of this new composition on different properties of bone china, after curing at 1260 °C for 3 hours, was investigated. The results showed that the physical and mechanical properties of the sample containing 50 wt% anorthite compared to the typical bone china improved and only 8.7% of the whiteness index diminished. Also the microstructure of samples containing Anorthite were observed without thermal crack and almost uniform distribution of Anorthite and quartz crystals in the heterogeneous glass matrix.
