High temperature biaxial strength of porous mullite-alumina and mullite-zirconia ceramics

Excerpt

Hot gas cleaning in coal combustion and gasification in the power generation industry is achieved by using porous ceramic filters [1]. These ceramic filters are high in porosity (up to 80%), have good thermal shock resistance and adequate gas permeability. In service, the filters are subjected to repeated impacts from fine particles (8 μm or greater) at velocities of about 50 mm/s in a gas stream at temperatures ranging from 400 °C to 1,000 °C. Therefore, the ceramic filter element must be able to withstand the contact of particles, the sudden temperature increase at the face of the filter and the pressure differential due to the gas. It is well known that mullite-based ceramics exhibit excellent thermal shock resistance [2]. In this communication we report the biaxial strength of porous mullite-alumina (designated MA) and mullite-zirconia (designated MZ) ceramics over a range of temperatures up to 1,250 °C. …