Effect of ceramic powder fineness on mullite-zirconium ceramic properties

Results are provided for a study of the development of high-temperature mullite-zirconium ceramic with use of activated ceramic powders prepared by grinding for different times with addition of illite clay, and from pure oxide powders. It is shown that increased activity and amorphicity of ground particles considerably promotes formation of mullite phase at 1200°C, and also transition of the monoclinic modification of ZrO2 to tetragonal, particularly with an increase in firing temperature. It is proposed that as a result of rapid “freezing” the structure retains the high-temperature modification of ZrO2, having a tendency with slow ceramic cooling to transform into the monoclinic modification.