Abstract
Si3N4 possesses excellent mechanical and electrical properties and is an ideal substitute for AlN in the fabrication of electronic substrates. In order to deal with the heat from electronic devices and the thermal shocks in service, high thermal conductivity is required. Recent studies have shown that sintering additive systems greatly influence the sinterability and thermal conductivity of Si3N4. The thermal conductivity of Si3N4 with Y2O3-MgO as sintering additives was investigated. Several kinds of Si3N4 with 5 wt% Y2O3 and 1-4 wt% MgO were gas pressure sintered at different temperatures. Results show that the thermal conductivity is over 40 W/m.K and that it is affected by the sintering conditions and the amount of MgO. Combining XRD and SEM observations, the microstructure of Si3N4 was studied to elucidate the relationship between the processing parameters and the thermal conductivity. 9 refs.