Dispersion strengthening gel-casting RBSiC by organic precursor impregnation
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摘要: 针对凝胶注模成型的反应烧结SiC空间反射镜材料,进行有机物前驱体浸渍处理,制备了具有细小次生-SiC均匀分布于基体的SiC陶瓷.研究了浸渍工艺对SiC密度及微观结构的影响.未经浸渍处理的样品反应烧结后密度为2.945 g/cm3,一次浸渍后密度增至2.969 g/cm3,二次浸渍后密度增至3.011 g/cm3.并随浸渍次数的增加,显微结构中细小SiC所占比例随之增加,即在反应烧结过程中,通过浸渍引入的碳与硅反应生成细小的-SiC弥散于基体.对样品进行了三点弯曲性能测试,未经浸渍处理的样品抗弯强度为308 MPa,一次浸渍处理强度为339 MPa,强度提高10.1%,二次浸渍处理强度为380 MPa,强度提高23.4%,大幅提高了力学性能.Abstract: The gel-casting of reaction bonded silicon carbide, which is a material of space mirror, was processed by organic precursor impregnation. A silicon carbide ceramic component with fine secondary -SiC distributed uniformly in the matrix was prepared. The density and the microstructure in the impregnation process were investigated. The density of the sample without impregnation process was 2.945 g/cm3 after reaction sintered. Density increased to 2.969 g/cm3 after one time impregnation, and increased to 3.011 g/cm3 after two times impregnation. The proportion of fine SiC in microstructure went up with the increasing of the impregnation times. In which the reaction sintered process, the carbon introduced by impregnation and silicon reacted to form fine -SiC dispersed in matrix. Bending test was conducted for the samples. The bending strength of the sample without impregnation process was 308 Mpa. Bending strength increased to 339 Mpa after one time impregnation, strength increased by 10.1%, and increased to 380 MPa after two times impregnation, strength increased by 23.4%, which improve the mechanical properties greatly.
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Key words:
- gel-casting /
- precursor impregnation /
- reaction bonded silicon carbide
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