结合方式对碳化硅浇注料氮化后抗热震性和显微结构的影响

摘要

研究了铝酸钙水泥(CAC)+二氧化硅微粉(MS)结合、水硬性氧化铝(HA)+二氧化硅微粉(MS)结合、二氧化硅溶胶结合的3种结合方式对氮化处理后碳化硅浇注料抗热震性和显微结构的影响.结果显示:3种结合方式制备的试样经600、800和1 100℃水冷1次热震后的残余抗折强度和强度保持率都随着温度的升高而降低,但在1 100℃热震后,3种结合方式的试样的残余抗折强度相当,二氧化硅溶胶结合的浇注料具有较好的抗热震性.分析表明,本试验的3种结合体系中,无水泥结合方式的试样中原位生成的SiAlON具有更大的长径比,特别是纤维状的SiAlON,对高温下结构的保持和抗热震性的提高更为有利.%Effects of three binding systems, namely, calcium aluminate cement + microsilica (CAC + MS), hydratable alumina + microsilica (HA + MS) ,and silica sol,on thermal shock resistance and microstructure of SiC based castables after nitridation were researched. The results show the residual modulus of rupture and its residual rate of specimens with three binding systems after one water quenching cycle at 600,800 and 1 100°C decrease with temperature rising,but their residual modulus of rupture after thermal shock at 1 100 °C is equivalent,and the castables bonded by silica sol have good thermal shock resistance. The analysis shows SiAION with higher length-diameter ratio in-situ forms in the cement free specimen,especially fiber-shaped SiAION,which is very favorable to the structure maintenance and improvement of thermal shock resistance.