C/C复合材料高温长寿命抗氧化复合涂层研究

Investigation of the Multi-coating for High Temperature and Long Life Oxidation Protection of C/C Composites

采用包埋技术在C/C复合材料表面制备SiC-WSi_2/MoSi_2抗氧化复合涂层;通过恒温氧化实验以及X射线衍射分析、扫描电镜观察及能谱分析,研究了W、Mo含量对复合涂层微观结构和高温抗氧化性能的影响.结果表明:随着包埋粉料中W、Mo含量的增加,所制备复合涂层的厚度先增加后减小;含有10.0at% W和Mo制备的复合涂层具有相对较大的厚度和较为致密的结构,且WSi_2和MoSi_2含量相对较高;氧化过程中在涂层表面形成致密和稳定的SiO_2玻璃保护膜;在1500℃氧化315h后,带有该涂层的C/C试样仍然没有失重,且经过18次1500℃(?)室温急冷急热后涂层没有开裂和脱落,说明该涂层具有优异的抗氧化和抗热震性能.

A SiC-WSi2/MoSi2 multilayer oxidation protective coating for carbon/carbon （C/C） composites was prepared by pack cementation. Effects of the total content of W and Mo on the microstructure and high temperature anti-oxidation property of the multi-coating were studied by XRD, SEM, EDS and isothermal oxidation test. The results show that with the total content of W and Mo increasing in the pack powders, the as-received multi-coating thickness first increases and then decreases. The multi-coating with 10.0at% （W and Mo） has a thicker, denser structure and higher content of WSi2 and MoSi2 than those with 0at%, 8.4at% and 13.1at% （W and Mo）. A stable and dense glassy SiO2 film can be formed on the coating surface with 10.0at% （W and Mo） during the oxidation test. The coated specimen with 10.0at% （W and Mo） has no weight loss after oxidation in air for 315h at 1500℃ and no cracks after thermal cycling between 1500℃ and room temperature for 18 times, which implies that the multi-coating has excellent oxidation protective ability and thermal shock resistance.