Abstract
As a traditional structural material, Si3N4 has superior mechanical properties, good electronic properties but low thermal conductivity (about 20 W/mK at room temperature). It has been shown that sintering additives influence the sinterability and thermal conductivity of Si3N4 greatly. The thermal conductivity of Si3N4 with CeO2-MgO sintering aids was investigated. Several kinds of Si3N4 with 5 wt% CeO2 and 0-5 wt% MgO were gas-pressure-sintered at different temperatures. The thermal conductivity and electrical properties of sintered samples were determined. Results showed that the thermal conductivity of the Si3N4 increased from 32 W/m.K to 62 W/m.K by controlling the sintering temperature and the additive content with all the good electrical properties maintained. The sintering temperature and the MgO content greatly affected the thermal conductivity. The microstructure of Si3N4 was studied to elucidate the relationship between the processing parameters and thermal conductivity.