炭/炭复合材料表面Mo-Si熔浆涂层中剩余Al对其1370℃抗氧化性能的影响

来忠红1; 2|　方海涛1|　左　昕 3|　全在昊2|　孟松鹤4|　朱景川1

炭/炭复合材料表面Mo-Si熔浆涂层中剩余Al对其1370℃抗氧化性能的影响

1. 哈尔滨工业大学材料科学与工程学院|黑龙江哈尔滨 150001;

韩国机械研究院材料工艺系|韩国昌源 641-010;

哈尔滨工业大学化工学院|黑龙江哈尔滨 150001;

4.
哈尔滨工业大学复合材料与结构研究所|黑龙江哈尔滨 150001

基金项目: 黑龙江省博士后基金.

详细信息

中图分类号: TB333
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出版历程
- 录用日期: 2013-07-16
- 刊出日期: 2013-06-20

Effect of Al content in an Al/Si layer on the oxidation behavior of the Mo/Si-Al/Si double-layer coated C/C composites at 1370℃

LAI Zhong-hong1,
2

1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;

Department of Materials Technology, Korea Institute of Machinery &|Materials, 66 Sangnam-Dong, Changwon 641-010, Korea;

School of Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China;

4.
Research Center for Composite Materials, Harbin Institute of Technology, Harbin 150001, China

Funds: Post-Doctor Foundation of Heilongjiang Province.

摘要

摘要: Si粉预涂层中添加Al能够有效阻止液态Si过度渗入C/C复合材料内部。实验考察Al添加剂对C/C复合材料表面Mo-Si熔浆涂层抗氧化性能的影响，对比研究了Si预涂底层中Al添加量分别为6%和10%时，Mo-Si熔浆涂层C/C复合材料1370℃的氧化行为。借助金相显微镜、X射线衍射仪和扫描电镜及能谱仪等分析手段对比分析Al含量不同的两种涂层氧化前后的组织结构，探讨了过量Al添加对涂层C/C复合材料氧化行为的影响机理。结果表明，Al-Si预涂底层中Al含量达到10%时，Mo-Si熔浆涂层中出现了散布于MoSi₂颗粒周围的剩余Al相；1370℃氧化过程中，含有剩余Al相的Mo-Si熔浆涂层C/C复合材料抗氧化性能迅速减弱。氧化过程中，涂层中剩余Al相向外扩散，在涂层内部留下相互连通的空洞，成为氧气扩散的通道，降低了涂层的氧阻挡能力；此外，剩余Al相在向外扩散过程中氧化生成含有Al₂O₃的疏松多孔的氧化层，不能有效阻止氧的扩散。这两个因素最终导致含有剩余Al相的涂层丧失防护能力，使得C/C复合材料基体氧化失重。
- C/C复合材料 /
- Mo-Si熔浆涂层 /
- 剩余Al相 /
- 氧化行为
Abstract: A Mo/Si slurry was coated onto the surface of Al/Si-coated carbon fiber reinforced carbon (C/C) composites and vacuum-sintered to form a fused double-layered coating. The effect of the Al content (6 and 10 mass%) in the Al/Si layer on the oxidation resistance of the composites was investigated. Results indicate that the presence of Al effectively prevents liquid Si infiltration into the composites. The composite with the 10 mass% Al has a much lower oxidation resistance than that with the 6 mass% Al. It is revealed that when the Al content is 10 mass% an Al phase dispersed around MoSi₂ grains is found in the Mo/Si layer, which decreases the oxidation resistance of the composite at 1370℃. This can be ascribed to voids generated within the Mo/Si layer due to the outward diffusion of Al and pores in Al₂O₃ formed during oxidation, which provide paths for oxygen diffusion.
- C/C composite /
- Mo-Si fused slurry coating /
- Residual Al /
- Oxidation behavior