MoSi_2添加对再结晶碳化硅(R-SiC)微观结构和体积电阻率的影响  

Effect of MoSi_2 Addition on Microstructure and Volume Resistivity of R-SiC

作　　者：高朋召[1] 汪文祥[1] 公伟伟[1] 肖汉宁[1] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2011年第5期69-73,共5页Journal of Hunan University:Natural Sciences

基　　金：湖南大学'中央高校基本科研业务费专项资金-青年教师科技创新扶持项目'资助

摘　　要：在一定粗细颗粒配比的SiC粉体中添加不同量的MoSi2,进而在2 300℃烧结得到MoSi2/R-SiC复合材料.采用SEM,XRD,力学性能测试、阻抗分析仪等方法研究了MoSi2添加量对复合材料微观结构、组成、力学和电学性能的影响.结果表明:在2 300℃所得的复合材料中,SiC为6H型,MoSi2转化为六方晶型的Mo4.8Si3C0.6,其主要原因是高温下液相MoSi2逐渐失去Si,同时与SiC发生反应转变为低硅含量的硅钼炭化合物所致.硅钼炭化合物主要以涂层的形式包覆在SiC颗粒的表面,随添加量的增加,涂层逐渐增厚,当添加量超过10%,部分Mo4.8Si3C0.6填充在SiC空隙中;复合材料的密度和表观气孔率随Mo-Si2添加量的增加逐渐增加,力学性能变化不大,但体积电阻率显著降低.同时对所得材料的导电机理进行了初步的探讨.MoSi2/R-SiC composite were obtained with different amount of MoSi2 in the SiC mixture powder and then sintered at 2 300 ℃.The XRD,SEM and impedance analyzer were used to study the microstructure,composition and volume resistivity.Experiment results showed that the 6H-SiC and Mo4.8Si3C0.6 with hexagonal structure were the main composition in materials obtained.The formation process was liquid MoSi2 losing Si and transforming into Mo-Si-C compounds and then reacting with SiC.The SiC grain was coated with Mo4.8Si3C0.6 compound.With the increase of additives,the thickness of the Mo4.8Si3C0.6 coating on SiC particles increased,and finally filled in the porosity in composite when the additive exceeded 10%.The density and porosity of the material increased at the same time.The mechanical properties changed little but the volume receptivity decreased significantly.Finally,the electronic conductive mechanism of the materials was discussed.

关 键 词：碳化硅 MOSI2 力学性能 体积电阻率 

分 类 号：TB35[一般工业技术—材料科学与工程]