MgAl_2O_4-LaCrO_3 Insulator Materials for the Microwave Sintering of Electronic Oxide Ceramics

The MgAl2O4-LaCrO3 insulator materials for the microwave sintering of electronic oxide ceramics were made by the mixing of MgAl2O4 spinel materials with superior thermal properties and LaCrO3 perovskites materials with high efficiency absorption of microwave. The samples for microwave sintering were placed in the enclosure made of the insulator materials, and the outer insulator enclosure were made of Al2O3 ceramic and Al2O3 fiber materials. Due to the thermal protection to the samples during the microwave sintering and especially in the rapid cooling procedure, the design of this kind insulating system solved the problems of thermal cracks often occurred in the microwave sintering of many electronic oxide ceramics, such as CoMnNiO series NTC ceramics, BaTiO3 based PTC, LaCrO3-based ceramics, and produce a homogeneous heating for the samples in the microwave sintering, and gain crack-free and dense ceramic samples. The highest temperature of the MgAl2O4-LaCrO3 insulator materials applied can be up to 1600℃.