Mo_5Si_3-MoSi_2/SiC复合涂层的高温抗氧化行为分析  

Analysis on the oxidation behavior of Mo_5Si_3-MoSi_2/SiC multi-coating at high temperature

作　　者：杨鑫[1] 邹艳红[2] 黄启忠[1] 苏哲安[1] 常新[1] 谢志勇[1] 张明瑜[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]中南大学材料科学与工程博士后流动站,长沙410083

出　　处：《复合材料学报》2009年第4期119-125,共7页Acta Materiae Compositae Sinica

基　　金：国家'973'计划项目(2006CB600901);国家自然科学基金(50772134;50802115)

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%。To improve the anti-oxidation property of graphite at high temperature, an Mo5 Sia- MoSi2/SiC multicoating was prepared by the chemical vapor reaction （CVR） and slurry method. The structure of the multi-coating was studied by XRD, SEM and EDS analysis, and the oxidation behavior of the multi-coating at high temperature was investigated by the isothermal oxidation test and thermodynamics calculation. The results show that the Mo5Si3 and MoSi2 phases in the multi-coating are prone to produce the reactions of forming the MoOa 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%.

关 键 词：石墨 抗氧化涂层 SIC MO5SI3 MOSI2 

分 类 号：TB332[一般工业技术—材料科学与工程]