摘要
采用包渗法在Mo及Mo-W基体上分别制备MoSi2及(Mo,W)Si2涂层,研究了W掺杂对MoSi2涂层抗氧化性能的影响规律和作用机理。结果表明,W元素固溶到MoSi2涂层中,形成(Mo,W)Si2固溶体,涂层微观结构更加致密化。在1600℃高温下静态氧化,(Mo,W)Si2涂层抗氧化失效时间长达70 h,1200℃下氧化1000 h仍具有良好的防护性能,抗氧化性能大幅提升。加入W元素阻碍了Si元素与基体间的扩散反应,降低了涂层中Si元素的消耗速率,显著增强了(Mo,W)Si2涂层抗高温氧化性能。在500℃低温下静态氧化50 h,与MoSi2涂层相比,(Mo,W)Si2涂层氧化产生明显的"Pest"现象,涂层严重粉化失效。加入W元素降低了涂层中Si元素的扩散速率,导致低温下涂层表面无法形成致密氧化层,加剧涂层的快速氧化。
MoSi2 and(Mo,W)Si2 coatings were prepared on Mo and Mo-W substrates respectively by means of pack cementation,and the effects and mechanisms of W element doping on the oxidation resistances of MoSi2 coating were investigated systematically.XRD,SEM and EDSwere used to determine the phase structure,morphology and composition of the coatings.The results showed thatW element was dissolved inMoSi2 coating in the form of(Mo,W)Si2 solid solution,and the microstructure of(Mo,W)Si2 coating was denser compared with that of MoSi2 coating as a result of W element doping.After static oxidation at1600 ℃,the antioxidant life of(Mo,W)Si2 coating reached 70 h,while MoSi2 coatingwas failed after 25 h oxidation due to severe weight loss.Moreover,(Mo,W)Si2 coating exhibited excellent high-temperature protection performance after oxidation at 1200℃ for 1000 h.At the initial stage of the oxidation,the oxidation rate of(Mo,W)Si2 coating was higher than that of MoSi2 coating owing to W element doping,which led to lower formation velocity of dense oxide layer on the surface of(Mo,W)Si2 coating.After the dense SiO2 covering the surface completely,the oxidation rate of(Mo,W)Si2 coatingdecreased dramatically.The diffusion reaction between the Si element and the substrate was hindered by the addition of W element,the consumption rate of Si element in the coating was reduced remarkably,and the high-temperature oxidation resistance of(Mo,W)Si2 coating was enhanced significantly.After static oxidation at 500 ℃,comparing withMoSi2 coating,(Mo,W)Si2 coating exhibited a typical "Pest" phenomenon after oxidation for 50 h,and the coating failed in the form of disintegration.The addition of Welement reduced thediffusi on rateofSielement in the coating,therefore,a dense oxide layer could not be formed on the coating surface at low-temperature,which caused the rapid oxidation of the coating.
作者
毛绍宝
杨英
李海庆
张世宏
Shaobao MAO;Ying YANG;Haiqing LI;Shihong ZHANG(School of Material Science and Engineering, Anhui University of Technology, Ma'anshan, Anhui 243002, China;Research Center of Modem Surface and Interface Engineering, Anhui University of Technology, Ma'anshan, Anhui 243002, China;Aerospace Research Institute of Materials & Processing Technology, China Academy of Launch Vehicle Technology, Beijing 100076, China)
出处
《过程工程学报》
CAS
CSCD
北大核心
2019年第4期826-835,共10页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:51671002)
