MoSi_2-SiC复合材料制备及抗热震性能研究  

Preparation and Thermal Shock Resistance of MoSi_2-SiC Composites

作　　者：雷乃旭 王文武 万龙刚 吴吉光 LEI Nai-xu;WANG Wen-wu;WAN Long-gang;WU Ji-guang(State Key Laboratory of Advanced Refractories,Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.,Luoyang 471039,China)

机构地区：[1]中钢集团洛阳耐火材料研究院先进耐火材料国家重点实验室,洛阳471039

出　　处：《人工晶体学报》2018年第5期1070-1074,共5页Journal of Synthetic Crystals

摘　　要：本文采用直接熔渗法制备二硅化钼-碳化硅(MoSi_2-SiC)复合材料。以碳化硅(SiC)(粒度为0~2.5 mm、≤240目)为主要原料,水溶性树脂为结合剂,经混炼、成型、烘干后得到SiC坯体,再用二硅化钼(MoSi_2)(D_(50)=3μm)粉末掩埋SiC坯体,在真空条件下2000℃保温3 h进行熔渗烧结,制备出MoSi_2-SiC复合材料。采用阿基米德排水法研究了MoSi_2-SiC复合材料的显气孔率、体积密度;采用三点抗弯法测试了MoSi_2-SiC复合材料1400℃抗折强度;采用热线法测试了MoSi_2-SiC复合材料导热系数;采用X射线衍射测试了MoSi_2-SiC复合材料的物相组成;采用SEM测试了MoSi_2-SiC复合材料的显微结构;分别采用风冷法和水冷法对比研究了MoSi_2-SiC复合材料、重结晶碳化硅(R-SiC)、氮化硅-碳化硅(Si_3N_4-SiC)三种材料抗热震性。结果表明:MoSi_2在烧结过程中部分发生分解,生成了Mo_5Si_3,MoSi_2、Mo_5Si_3填充于SiC的内部并实现烧结致密化,使MoSi_2-SiC复合材料的显气孔率显著降低至5.7%,体积密度为3.59 g·cm^(-3)。MoSi_2-SiC复合材料中MoSi_2、Mo_5Si_3含量分别为10wt%~15wt%、3wt%~5wt%。1000℃下MoSi_2-SiC的导热系数为46.5 W·m^(-1)·K^(-1),显著高于R-SiC(28.3 W·m^(-1)·K^(-1))材料、Si_3N_4-SiC(16.8 W·m^(-1)·K^(-1))材料。综上所述,MoSi_2-SiC复合材料的抗热震性能显著优于R-SiC材料、Si_3N_4-SiC材料。Molybdenum disilicide bonded silicon carbide（MoSi2-SiC） composites have been produced by direct infiltration method. The main ingredient were used by industrial pure silicon carbide（SiC）（2. 5 ～0 mm,≤0. 061 mm）. Using Water-soluble resin as the binder,mixing,sharping,drying. The green bodies,got by this way,which were covered by Molybdenum disilicide（MoSi2）（D（50）= 3μm） and infiltration sintering at 2000 ℃ for 3 h under vacuum. The apparent porosity and bulk density of MoSi2-SiC composites were studied by Archimedes drainage method. The flexural strength at 1400 ℃ was tested by the three-point bending test method. The thermal conductivity was tested by the hot wire method. The phase composition was measured by X-ray diffraction. The microstructure was tested by Scanning Electronic Microscopy（SEM）. The thermal shock resistance of MoSi2-SiC composites,recrystallized silicon carbide（R-SiC） materials and silicon nitride bonded silicon carbide（Si3N4-SiC） materials were compared by 5 times thermal shocking water-cooled and air-cooled at 1300 ℃. The results indicate that MoSi2 partially decomposed to Mo5Si3 during sintering and they were both filled into the interior of SiC andsintered to densification, which markedly decreased the apparent porosity to 5. 7%, bulk density increased to 3. 59 g·cm-3. The contents of MoSi2 and Mo5Si3 in MoSi2-SiC composites are respectively10 wt% ～ 15 wt% and 3 wt% ～5 wt%. The thermal conductivity at 1000 ℃ is 46. 5 W · m-1·K-1,significantly higher than R-SiC and Si3N4-SiC. As stated above,the thermal shock resistance and high temperature bending strength of MoSi2-SiC composites was significantly better than that of R-SiC and Si3N4-SiC.

关 键 词：MOSI2-SIC复合材料 直接熔渗法 导热系数 抗热震性 

分 类 号：O649[理学—物理化学]