Synthesis of 30 wt%BAS/Si 3N 4 composite by spark plasma sintering

Abstract

30 wt%BAS/Si 3N 4 composite was fabricated via spark plasma sintering (SPS) process. The as-sintered specimens were subsequently heat-treated at 1800 °C to further optimize the microstructure and mechanical properties. The results show that SPS could effectively promote the reaction synthesis of BAS glass and α- to β-Si 3N 4 phase transformation, resulting in a dense 30 wt%BAS/Si 3N 4 composite with fine elongated β-Si 3N 4 grains dispersed in the continuous BAS glass matrix. Post heat-treatment could realize the complete crystallization of BAS and microstructural optimization. The obtained composite exhibits excellent mechanical properties compared to unreinforced BAS glass–ceramic. The flexural strength and fracture toughness could reach 944 MPa and 8.9 MPa m 1/2, respectively, which reach the level of conventional Si 3N 4 composites sintered by traditional sintering process. SPS followed by heat-treatment provides a feasible way to control microstructure, thus optimizes the mechanical performance of glass–ceramics matrix composites.