Thermal conductivity of unidirectionally oriented Si3N4w/Si3N4 composites

β-silicon nitride whiskers were aligned unidirectionally in silicon nitride sintered with 2 wt% Al2O3 and 6 wt% Y2O3. It was be densified by the Gas Pressure Sintering (GPS) method. Thermal conductivity of the sintered body with different amount of β- silicon nitride whiskers was measured by the direct contact method from 298 K to 373 K. This unidirectionally oriented β-silicon nitride whiskers grew into the large elongated grains, and improved also the thermal conductivity. The amount of β-silicon nitride whiskers changed the microstrcuture, which changed the thermal conductivity.