不同增强体对SiC涂层性能的影响

Influence of different reinforcement on performance of SiC coating

采用3种工艺,以石墨为基体制备SiC抗氧化涂层,通过引入不同组分优化涂层相结构并对其性能进行研究。分别测试了不同制备工艺下的试样在1400℃下的抗氧化性能。通过分析试样氧化前后表面及侧面的SEM图以及涂层XRD衍射结果,研究涂层形貌、相结构及氧化机理。实验结果表明,同时引入SiC晶须及MoSi2的涂层在1400℃下氧化10h,氧化失重不超过1%,表现出良好的抗氧化性能;SiC晶须的存在能够减少涂层微裂纹的产生,减少渗Si过程中Si对基体的腐蚀;MoSi2和Mo的加入均能提高涂层质量并表现出较好的自愈合能力。

SiC coating was prepared by three technologies on graphite with the purpose of optimizing the phase structure and researching the performance of antioxidant coating. The weight loss of different samples oxidated at 1400℃ for 10h was tested. The surface and cross-section morphology images of the coating before and after oxidation were analyzed by scanning electron microscopy （SEM）. Phase structures were analyzed by X-ray diffraction （XRD）. The research indicates that the coating shows better oxidation resistance by introducing SiC whiskers and MoSi2 at the same time, with the weight loss below 1% after oxidation at 1400℃ for 10h. The SiC whiskers can effectively decrease the crack of the coating in the oxidation process, and avoid the excessive pene- tration of silicon to protect the matrix from being excessively corrosion. Adding MoSi2 and Mo, the coating shows much better oxidation resistance and self-healing ability.