SiC/Mo-Si复合涂层C/SiC复合材料的氧化性能

Oxidation behavior of C/SiC composites with a SiC/Mo-Si multilayer coating

  • 摘要: 采用化学气相沉积法(CVD)和刷涂法在C/SiC复合材料表面制备抗氧化涂层。该涂层由致密的CVD SiC层和多孔的Mo-Si层交替组成,其结构从里到外为:CVD SiC层→Mo-Si层→CVD SiC层→MoSi层→CVD SiC层。涂层试样于1400℃的氧化实验和1400℃100℃的热震实验结果表明:在氧化和热震过程中,涂层均保持完整,没有出现脱落和掉块等失效现象。经1400℃、150h氧化后,涂层试样的失重率仅为0.25%,失重速率为6.61×10-6 g · cm-2 · h-1。在热震过程中,涂层试样基本保持氧化增重。经25次和50次热震后,涂层试样的弯曲强度保持率分别为95.73%和81.61%。SiC/Mo-Si复合涂层具有优异的抗氧化和抗热震性能,可对C/SiC复合材料提供1400℃、长时间的氧化防护。

     

    Abstract: A SiC/Mo-Si multilayer coating was prepared on the surface of C/SiC composites by chemical vapor deposition (CVD) combined with slurry painting. The coating was composed of a dense CVD SiC coating alternating with a porous MoSi layer. From inside to outside the coating consisted of CVD SiC, Mo-Si, CVD SiC, Mo-Si and CVD SiC . The coating remained intact and no obvious failure such as destruction or spalling was found during oxidation at 1400℃ and thermal shock between 1400℃ and room temperature. The mass loss and mass loss rate of the coated sample were only 0.25% and 6.61×10-6g · cm-2 · h-1, respectively after oxidation at 1400℃ for 150h. The flexural strength retention was 95.73% and 81.61% after 25 and 50 thermal cycles respectively and mass of the coating generally increased after oxidation. The SiC/Mo-Si multilayer coating showed excellent antioxidation ability and a thermal shock resistance and could effectively protect the C/SiC composites at 1400℃ for a long time.

     

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