硅粉加入量对Si3N4结合刚玉材料性能的影响

摘要

为了研究Si3N4结合刚玉材料的性能,以电熔棕刚玉颗粒(ω(Al2O3)＞95.4％,粒度3～1和≤1 mm)、电熔棕刚玉细粉(ω(Al2O3) ＞95.4％,d50=75 μm)和硅粉(ω(Si) ＞99.0％,d50=75 μm)为主要原料,通过原位氮化烧结工艺制备了Si3 N4结合刚玉复合材料,研究了硅粉加入量(ω)分别为10％、15％和20％时材料的介电性能、力学性能及抗热震性能,并对其物相和显微结构进行分析.结果表明:硅粉加入量(ω)由10％增加到20％,材料的常温力学性能及热膨胀系数下降,抗热震性能有明显的提高;当硅粉加入量(ω)为20％时,复合材料在1 100℃水冷热震50次时,试样表面仍无剥落,表现了良好的抗热震性.%Si3N4 bonded corundum composites were prepared using fused brown corundum particles (Al2O3 ＞95.4 mass％,3-1 mm,≤1 mm) and fines (Al2O3 ＞95.4 mass％,d50 =75 μm),and silicon powder (Si ＞ 99.0 mass％,d50=75 μm) as main starting materials with the in-situ nitridation sintering method.Effects of silicon powder additions (10％,15％,20％,by mass percent,the same hereinafter) on dielectrical property,mechanical properties,and thermal shock resistance were researched.The phase evolution and microstructure were analyzed.The results show that with silicon powder addition increasing from 10％ to 20％,the cold mechanical properties and the thermal expansion coefficient of the materials decrease,but the thermal shock resistance enhances greatly;with 20％ silicon powder addition,the material shows good thermal shock resistance (50 cycles,1 100 ℃ water-cooling) without surface spalling.