研究了粗碳化硅(SiC)颗粒的加入对再结晶碳化硅陶瓷(R-SiC)抗热震性能的影响;通过不同温度下热震(水淬试验)后测试不同配方陶瓷的残余强度来评价其抗热震性能,并测试了R-SiC陶瓷在30~1 200℃的平均线膨胀系数,通过SEM分析了材料的显微结构及热震损伤机制.结果表明:随着粗SiC颗粒(250 μm)含量的提高,R-SiC陶瓷的密度、临界热震温差均先升后降;含有50 % 250 μm SiC颗粒陶瓷的密度最大,为2.60 g·cm-3,线膨胀系数最小,为4.60×10-6 /℃,抗热震性能最好,其临界热震温差达395℃;250 μm SiC颗粒的引入使得R-SiC在热震过程中产生大量的微裂纹,能够迅速吸收存储在材料中的弹性应变能,从而提高其抗热震性能.

The effects of coarse particles of silicon carbide (SiC) addition on the thermal shock resistance of recrystallized silicon carbide(R-SiC) were investigated.The thermal shock resistance of the ceramics with different formulas was evaluated through residual strength measurement by thermal shock (water quenching) tests at different temperatures.The average linear thermal expansion coefficient of the R-SiC ceramics was tested at 30-120℃.The microstructure of the ceramics was analyzed by SEM and the thermal shock damage mechanism was investigated.The results show that as the increase of the coarse particle SiC (250 μm) addition,the density and critical thermal shock temperature difference of the R-SiC ceramics increased first and then decreased.The ceramic with 50 wt % addition of 250 μm SiC particles had the maximum density of 2.60 g·cm-3,the minimum thermal expansion coefficient of 4.60×10-6/℃,the best thermal shock resistance and critical thermal shock temperature difference of 395℃.A large number of microcracks formed during the R-SiC thermal shock process as the addition of 250 μm SiC particles which absorbed rapidly elastic energy deposited in the material and improved its thermal shock resistance.