摘要
在氧化性环境中,高于400℃时碳纤维开始氧化,限制了Cf SiC复合材料的应用。通过在Cf SiC复合材料表面制备抗氧化涂层体系,可以有效地保护碳纤维不被氧化。本实验制备了含CVD SiC粘接层、自愈合功能层和CVD SiC抗冲蚀层的三层涂层体系,并进行了氧化失重试验。氧化失重试验结果表明,仅有CVD SiC涂层的试样氧化失重率较大,不能有效地保护材料,而含有自愈合功能层的三层涂层体系的材料试样,在800℃～1200℃的氧化失重率非常小,1000℃下氧化288h的失重率仅为2.3%,弯曲强度仍保持为452.9MPa。同时实验发现,试样在氧化失重试验后,其CVD SiC涂层的表面形貌有明显改变,这主要是由SiC氧化形成SiO2薄膜所致,并且在1200℃下所生成的SiO2薄膜有表面收缩趋势,具有液相膜的部分特征。
The hindrance which currently precludes the use of Cf/SiC composites is the oxidation of carbon fiber at the temperature higher than 400℃.Therefore,it is necessary to develop coatings capable of protecting Cf/SiC components from oxidation.This coatings consist of three layers,a CVD-SiC bonding layer,a self-sealing active layer by forming glassy phases on exposure to oxygen,and a CVD-SiC erosion resistant layer.Oxidation tests was carried out.The results indicated that the samples with only CVD-SiC coating have much mass loss,and the samples with three layers of coatings including a self-sealing active layer have little mass loss from the temperature of 800℃ to 1200℃.Samples with self-sealing active layer which underwent an oxidation test at 1000℃ in the atmosphere for 288hr suffered only 2.3% mass loss and a residual strength of 452.9MPa.At the same time,CVD-SiC shows various appearance after oxidation at 800℃,1000℃,and 1200℃.The surface formed at 1200℃ has some liquid phase characteristics.
出处
《国防科技大学学报》
EI
CAS
CSCD
北大核心
2004年第4期57-61,共5页
Journal of National University of Defense Technology
基金
"863"基金资助项目(2002AA305102)
国家部委基金资助项目(41312011002)
