以两种不同配比Y2O3/Al2O3(A,2：3； B,3：1,总量15 wt%)为烧结助剂,通过添加不同质量分数的SiC粉体,反应烧结制备了高强度的氮化硅/碳化硅复相陶瓷。并对材料的相组成、相对密度、显微结构和力学性能进行了分析。结果表明：在1700℃保温2 h情况下,烧结助剂A 与B对应的样品中α-Si3N4相全部转化为β-Si3N4；添加5wt%SiC,烧结助剂A对应样品的相对密度达到最大值94.8%,且抗弯强度为521.8 MPa,相对于不添加SiC样品的抗弯强度(338.7 MPa)提高了约54.1%。SiC能有效改善氮化硅基陶瓷力学性能,且Si3N4/SiC复相陶瓷断裂以沿晶断裂方式为主。
With Y2O3:Al2O3 (A 2:3; B 3:1 total amount 15wt%) as sintering additives and SiC as the second phase, high flexural strength Si3N4/SiC composite ceramics were prepared via nitridation of Si powder. The phase composi-tion, relative density, microstructure as well as mechanical properties were investigated. The experimental results showed that theα→β-Si3N4 phase transformation could be completed at 1700℃ for 2 h with sintering additives A or B. With the sintering additive A and 5wt%SiC addition, the maximum relative density of 94.8%and maximum flex-ural strength of 521.8 MPa were obtained for the Si3N4/SiC composite ceramics. As compared with the specimen without SiC addition which flexural strength was 338.7 MPa, flexural strength of the above mentioned Si3N4/SiC composite ceramics was improved by 54.1%. SiC powder can effectively improve the mechanical properties of the specimen and the fracture of Si3N4/SiC composite ceramics followed the typical intergranular fractural mode.
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