Thermal Conductivity of Pressureless Sintered Silicon Nitride Material with LiYO_2 Additive

摘要

Si_3N_4 ceramics with different microstructures were prepared by pressureless sintering, using LiYO_2 as a sintering additive. The effect of microstructural parameters, such as grain size and volume of intergranular phase on thermal conductivity was studied. Materials with thermal conductivities of 26-38 W centre dot (m centre dot K~(-1)) were obtained by changing the amount of sintering additive. The highest conductivity was measured for the material with the least amount of additive. Since the phase composition is the same for all sintered materials the difference in thermal conductivity is attributed to the amount of glassy phase in the grain-junctions.