ZHAI Yanxia ¹, LI Zhaomin ¹, SUN Haibin ^1,3, ZHANG Yujun ²

(1. Shandong Bao new materials Co. Ltd., Laiwu 271114, Shandong, China; 2. Shandong University material liquid solid structure

and processing the Key Laboratory of Ministry of education, Ji'nan 250061, Shandong, China; 3. College of materials science and

engineering Shandong University of Technology Zibo 255000, Shandong, China)

Abstract: The preparation method and technological conditions of reaction sintering B₄C/SiC composite ceramics were determined, and the samples were characterized by metallographic microscope, XRD and SEM. The results show that the high-performance reaction-bonded B₄C/SiC composite ceramics can be obtained taking B4C and SiC powders with average particle size of 17 μm as raw materials, according to B₄C/SiC=0.6 B₄C , followed by reaction sintering at 1560 ℃ for 2 h. The bulk density, viker-hardness, bending strength and fracture toughness of samples are 2.92 g/cm³, 28.2 GPa, 376 MPa, 4.46 MPa·m^1/2, respectively. The phases are mainly SiC, B₄C, Si and a little B₁₂(B,Si,C)₃. The B4C particles are uniformly distributed in the continuous phase formed by SiC and Si.

Key words: Reaction bonded; B₄C/SiC composite; Sintering temperature; phase composition; microstucture