摘要
以AlN-Y2O3-La2O3为烧结助剂,在5.5 GPa,1 550℃下对c-BN-β-Si3N4复合材料进行了超高压烧结。借助X射线及扫描电镜对烧结样品进行了分析和观察,探讨了保温时间对产物的组成、形貌及力学性能的影响。结果表明:1)超高压条件下c-BN保持了原有的结构及形貌,发育良好的棒状β-Si3N4晶体均匀分布于烧结体中;α-Si3N4完全转变成β-Si3N4的时间随c-BN含量的增加而延长;烧结体相对密度和弯曲强度均随c-BN含量的增加而降低,硬度则随着c-BN含量的增加而增加,而相对密度的降低在一定程度上抵消了c-BN对硬度提高的贡献。2)c-BN质量分数为50%的复合材料同时具备较高的弯曲强度及硬度,其值分别为830 MPa与29.3 GPa。
c-BN-15-Si3N4 composite specimens were sintered under 5.5 GPa at 1 550 ℃ using AIN-Y2O3- La2O3 as sintering additive. The specimens were analyzed with XRD and SEM. The effect of holding time on phase compositions, micro morphology,and mechanical properties of the specimens was studied. The results show that. （1）under ultra-high pressure, c-BN remains its original structure and morphology,and well developed β-Si3N4 crystals uniformly disperse in the specimen;as c-BN content increases,the complete transformation time of α-SiaN4 to β-Si3 N4 prolongs, the relative density and flexural strength of the specimens decrease, but the hardness increases ;the decrease of the relative density counteracts the increase of the hardness to some degree;（2）when c-BN content is 50 mass%,the composites possess both high flexural strength and hardness,830 MPa and 29.3 GPa,respectively.
出处
《耐火材料》
CAS
北大核心
2012年第3期197-199,205,共4页
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