WANG Huifang ¹, ZHOU Ningsheng ¹, ZHANG Sanhua ²

(1. High Temperature Materials Institute, Henan University of Science and Technology, Luoyang 471003, Henan, China; 2. SinoSteel Luoyang Institute of Refractories Research Co., Ltd., Luoyang 473019, Henan, China)

Abstract: Effects of Si additive on physical properties, microstructure, cold crushing strength (CCS), cold modulus of rupture (CMOR), hot modulus of rupture (HMOR) at 800-1400 ℃, and thermal shock resistance (TSR) of specimens of SiC based castables added with 5-9% silicon powders and nitridized in nitrogen atmosphere at 1420 ℃ were researched. The main raw materials adopted involve black SiC, white fused alumina (WFA), microsilica (MS), reactive alumina(RA) and calcium aluminate cement (CAC). Chemical compositions and microstructure were analyzed by XRD, SEM and EDAX. The results show that the nitridation reaction was complete. The in-situ formed Sialon was in network state, which enhanced the strength. Residual MOR rate of specimens after thermal shock decreased with the rise of test temperature but with no relevance to the addition amount of Si.

Key words: vibration cast shaping; SiC; hot modulus of rupture; TSR