硅粉加入量对氮化后碳化硅基浇注料强度及热震稳定性的影响

摘要

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.%以黑碳化硅、烧结白刚玉粉(WFA)，二氧化硅微粉(MS)，氧化铝微粉(RA)，铝酸钙水泥(CAC)作为主原料，添加不同比例的硅粉，采用浇注成形、高温氮化的方法制备了碳化硅基耐火材料。研究了不同硅粉含量对试样常规物理性能、物相和显微结构、冷/热态强度及热震稳定性的影响。结果表明：氮化反应进行完全，原位形成的赛隆(Sialon)促进了SiC颗粒间及SiC颗粒与基质间的结合，交叉的网络状结构利于强度的提高。随着热震温度的提高，强度保持率下降，与硅粉加入量无关。