液硅渗透法制备SiBC改性C/CSiC复合材料

为了降低液硅渗透法制备C/C-SiC复合材料中残留Si的含量, 采用浆料浸渗结合液硅渗透工艺制备B₁₂(C, Si, B)₃改性C/C-SiC复合材料。通过分析不同比例B₄C-Si体系在不同温度的反应产物, 确定了B₁₂(C, Si, B)₃的生成条件。结果表明: B₄C和Si在1300℃开始反应, 生成少量B₁₂(C, Si, B)₃和SiC, 且B₁₂(C, Si, B)₃的生成量随反应温度的升高而增加; 当B₄C和Si的摩尔比为3:1、 反应温度为1500℃ 时, 产物为B₁₂(C, Si, B)₃和SiC; 液硅渗透法制备的C/C-SiC复合材料相组成为非晶态C、 β-SiC和B₁₂(C, Si, B)₃, 未见残留Si。

Fabrication of Si - B - C modified C/C - SiC composite by liquid silicon infiltration

In order to reduce the content of residual Si generated in the process of liquid silicon infiltration, B₁₂(C, Si, B)₃ modified C/C-SiC composite was prepared by a joint process of slurry impregnation and liquid silicon infiltration. By analyzing the products of B₄C-Si system with different B₄C/Si molar ratios after sintered at different temperatures, the formation condition of B₁₂(C, Si, B)₃ was studied. The results indicate that B₄C starts to react with Si at 1300℃, leading to the formation of a small amount of B₁₂(C, Si, B)₃ and SiC. The amount of B₁₂(C, Si, B)₃ generated in the reaction increases with increasing sintering temperature. The sintering product of B₄C-Si system with a B₄C/Si molar ratio of 3:1 at 1500℃ is composed of B₁₂ (C, Si, B)₃ and SiC. The C/C-SiC composite fabricated by liquid silicon infiltration is composed of amorphous C, β-SiC and B₁₂(C,Si,B)₃, and no residual Si is detected.