High temperature strength of ceramics

Deqing Yehui Ceramic Parts Manufacture Co., Ltd. is located in Deqing county, Huzhou City, ZheJiang Province, China. It is about 200km away from Shanghai seaport, we specialized in manufacturing Zirconia Ceramics and Alumina Ceramic parts with 10 years.

The high temperature resistance of structural ceramics is generally better, usually below 800°C, and temperature has little effect on the strength of ceramic materials. Compared with covalent bond ceramics, ion-bonded ceramics have poorer high temperature resistance. Generally speaking, in the lower temperature range, the fracture failure of ceramics is brittle behavior, that is, there is no plastic deformation, and the ultimate strain is very small, and it is very sensitive to small defects. However, in the high temperature zone, ceramics can produce small plastic deformation before fracture, the ultimate strain is greatly increased, and there is a small amount of elastoplastic behavior. In addition, the sensitivity of strength to defects varies greatly. The boundary between the low temperature zone and the high temperature zone that produces this material property change is usually called the brittle ductility transition temperature. The brittle ductility transition temperature is closely related to the ceramic chemical composition and the type of valence bond. Relevant, but also related to the microstructure of the ceramic, the composition of the grain boundary phase, especially the composition and content of the grain boundary glass phase. At high temperatures, above the brittle ductility transition temperature, the strength of most ceramic materials will decrease. For ion-bonded MgO ceramics, the brittle ductility transition temperature is very low, and the strength decreases with the increase of temperature almost from room temperature. The brittle ductility transition temperature of Al2O3 is about 900°C, the brittle ductility transition temperature of hot-press sintered Si3N4 is about 1200°C, and SiC ceramics can often withstand high temperatures of 1600°C.

Post time: Jan-03-2024