LIU Weiliang¹ ,TAN Jingang^1,2 ,KAN Yanmei ²

(1. Jingdezhen Ceramic Institute, Jingdezhen 333001; 2. State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai 200050)

Abstract: In this study, with ZrB₂ and SiC powders used as raw materials and Si₃N₄ as milling medium, ZrB₂-SiC composites were prepared by hot-press sintering. The relative density, microstructure and mechanical properties of the composites were investigated. Results showed that with the increase of ZrB₂ milling time and SiC volume content, the relative densities of the composites were first increased and then decreased a little. The best milling time of ZrB₂ was 8 hours and the best content of SiC was 20vol%. The relative density of ZrB₂+20vol%SiC composite is up to 98.3%, the flexural strength is 631±4MPa,the fracture toughness is 5.4±0.2 MPa·m^1/2. With the increase of ZrB₂ millng time, the fracture mode of the material changes from transgranular fracture mode to intergranular fracture mode.

Keywords: ZrB₂-SiC, densification, mechanical properties