THERMAL DIFFUSIVITY CONDUCTIVITY AND SPECIFIC-HEAT OF MULLITE-ZIRCONIA-SILICON CARBIDE WHISKER COMPOSITES/

The thermal diffusivity of mullite-ZrO2-SiCw materials was determined from 25 degrees to 1000 degrees C for composites in which the ZrO2 had different amounts of monoclinic and tetragonal phase, and varying SiC w content, At 25 degrees C the thermal diffusivity of the matrix mater ials increased with increasing amounts of monoclinic phase, and little or no anisotropy was seen, Composites with SiCw additions showed sign ificant increases in thermal diffusivity and anisotropy as compared wi th the matrix materials. With increasing temperature, thermal diffusiv ities of the matrices and their respective composites decreased, and a t 1000 degrees C differences mere small. Specific heat was determined from 25 degrees to 700 degrees C and thermal conductivity values calcu lated, Specific heat increased with temperature and was not compositio n dependent, except for one sample, Thermal conductivity values as a f unction of temperature followed the same trends as the thermal diffusi vity values.