Mo5Si3-MoSi2/SiC复合涂层的高温抗氧化行为分析

Mo₅Si₃-MoSi₂/SiC复合涂层的高温抗氧化行为分析

基金项目: 国家“973” 计划项目(2006CB600901) ; 国家自然科学基金( 50772134 , 50802115)

详细信息

中图分类号: TB332
计量
- 文章访问数: 2093
- HTML全文浏览量: 71
- PDF下载量: 970
出版历程
- 收稿日期: 2008-09-09
- 修回日期: 2008-12-17
- 刊出日期: 2009-08-14

Analysis on the oxidation behavior of Mo₅Si₃-MoSi₂/SiC multi-coating at high temperature

摘要

摘要: 采用化学气相反应法和料浆刷涂反应法，在石墨表面制备了Mo₅Si₃-MoSi₂/SiC复合涂层，借助X射线衍射仪、扫描电镜及能谱等分析手段，研究了涂层的结构；通过恒温抗氧化实验及热力学分析，重点研究了涂层的高温抗氧化行为。结果表明：在1823 K的氧化氛围中，复合涂层中的Mo₅Si₃、MoSi₂组元易氧化生成MoO₃气体并导致涂层失重；而氧化初期(0～6 h)涂层试样的增重则主要与SiC的惰性氧化主导有关。由于复合涂层各组元在高温下都能氧化生成SiO₂玻璃，使涂层具有良好的高温抗氧化及热震性能；经20 h、16次循环热震实验后，涂层试样的氧化失重率只有3.78%。
- 石墨 /
- 抗氧化涂层 /
- SiC /
- Mo₅Si₃ /
- MoSi₂
Abstract: To improve the anti-oxidation property of graphite at high temperature，an Mo₅Si₃-MoSi₂/SiC multi-coating was prepared by the chemical vapor reaction (CVR) and slurry method. The structure of the ulti-coating was studied by XRD，SEM and EDS analysis，and the oxidation behavior of the multi-coating at high emperature was investigated by the isothermal oxidation test and thermodynamics calculation. The results show that the Mo₅Si₃and MoSi₂ phases in the multi-coating are prone to produce the reactions of forming the MoO₃ gas in air at 1823 K and result in the mass loss，while the mass gain in the initial oxidation stage (0～6 h) is primarily attributed to the dominating passive oxidation of SiC. As the main phases of the multi-coating can oxidize and form the SiO₂ glass at high temperature，it enables the coating to have the excellent anti-oxidation ability and thermal shock resistance. After oxidation in air at 1823 K for 20 h and thermal cycling between 1823 K and room temperature 16 times，the mass loss of the coated sample is only 3.78%.
- graphite /
- anti-oxidation coating /
- SiC /
- Mo₅Si₃ /
- MoSi₂