MgSiN 2 Addition as a Means of Increasing the Thermal Conductivity of β‐Silicon Nitride

Si 3 N 4 powders with the concurrent addition of Yb 2 O 3 and MgSiN 2 were sintered at 1900°C for 2–48 h under 0.9 MPa nitrogen pressure. Microstructure, lattice oxygen content, and thermal conductivity of the sintered specimens were evaluated and compared with Si 3 N 4 , Yb 2 O 3 , and MgO addition. MgSiN 2 addition was effective for improving the thermal conductivity of Si 3 N 4 ceramics, and a material with high thermal conductivity over 140 W·(m·K) −1 could be obtained. For both specimens, lattice oxygen content was decreased with sintering time. However, the thermal conductivity of the MgSiN 2 ‐doped specimen was slightly higher than the MgO‐doped specimen with the same oxygen content.