Papers by Author: Zhong Qiu Li

Abstract: A novel technique to join ceramics was described using microwave heating. SiC was added in the interlayer as a microwave-absorbing material, joining of 95 Al2O3 was realized by raising temperature of SiC itself and then inducing microwave-absorbing of oxides. The strength of joining, microstructure of interlayer and mechanism of joining were investigated.

Abstract: LaPO4-ZrO2 composites were prepared by slip casting and pressureless-sintered in air. The effects of LaPO4 addition on microstructure and thermal shock resistance were addressed. The thermal shock resistance of the composites was evaluated by air quenching and a subsequent three-point bending test to determine the strength degradation. Comparisons were made with results from parallel experiments conducted using a ZrO2 ceramic without LaPO4 additions. The reference ZrO2 ceramic showed the expected substantial strength losses when thermally quenched from 470oC above room temperature. By contrast, the LaPO4-ZrO2 ceramics, while displaying reduced strength relative to the reference ZrO2 ceramics, exhibited minimal strength degradation under severe thermal shock conditions.

Abstract: A novel technique to synthesize mullite by the oxidation of Al-Si alloy powder was used for the manufacture of mullite via pressure molding. The mixed powder was consisted of powders of Al-Si alloy, Al2O3 and SiO2 and additives or powders of Al-Si alloy, Al2O3, SiO2 and ZrO2 and additives. Those mixed powders were milled in nonaqueous slurry in order to prevent the oxidation of Al-Si alloy. Then the green bodies were pressureless sintered in air at ≥1380 °C. The Oxidation caused an internal volume expansion, resulting in reducing shrinkage stresses during reaction- bonding of composites, which minimized the sensitivity to crack formation. Comparing with non zirconia reinforced mullite composites, the effect of the microstructure and mechanical properties of mullite composites were studied.