YB2C2: A new additive for fabricating Si3N4 ceramics with superior mechanical properties and medium thermal conductivity

Abstract

Si3N4 ceramics were hot-pressed with MgO and self-synthesized YB2C2 as sintering additives at 1800 °C for 2 h under the pressure of 60 MPa. The addition of YB2C2 played a significant role in the simultaneous achievement of superior mechanical properties and medium thermal conductivity of Si3N4 ceramics. Due to the existence of multilayer YB2C2 nanoplatelets, the flexural strength and fracture toughness of Si3N4 ceramics reached up to 1189.6 ± 43.7 MPa and 9.46 ± 0.14 MPa m1/2, respectively. Owing to the reaction between YB2C2 and native SiO2 on the surface of Si3N4 powders, the lattice oxygen was removed and the thermal conductivity of Si3N4 ceramics was about 77.0 W/(m·K).