摘要
CMAS沉积物(CaO-MgO-Al2O3-SiO2,CMAS)已经成为制约航空发动机涡轮叶片热障涂层应用的核心问题,其显著降低热障涂层服役寿命,严重的甚至堵塞叶片气膜冷却孔,导致合金基体烧蚀和失效。本文针对DZ40M钴基高温合金和其表面NiCrAlY涂层,模拟了热障涂层陶瓷层失效后,CMAS沉积物对合金基体和粘结层的腐蚀作用。针对1100℃预氧化10h后的样品,在涂抹相同面密度的CMAS沉积物后,在1100℃、1150℃、1200℃和1250℃条件下保温10h,系统分析了不同温度下CMAS对合金及NiCrAlY涂层表面氧化膜的破坏作用,通过XRD、SEM和EDS等手段,阐明了温度在1150℃以下,CMAS沉积物主要对氧化膜产生粘附及热应力影响,导致冷却过程中的氧化膜剥落;当温度高于1200℃时,CMAS逐步熔融或渗入氧化膜内部,导致氧化膜开裂剥落加速,对金属粘结层和基体的损伤破坏作用加剧。
CMAS(Cao-MgO-Al2O3-SiO2,CMAS)deposits have already been a crucial issue that limits the performance of TBCs(Thermal Barrier Coatings,TBCs)for aeroengine turbine blades which can significantly decrease the service lifetime of TBCs.What's more,CMAS deposits may severely block the air film cooling holes of blade and thus leads to the ablation and degradation of the underlying alloy substrate.In this paper,DZ40M cobalt-based superalloy and NiCrAlY coating were applied to simulate the corrosion effect of CMAS deposits on alloy substrate and bond coating after TBCs degradation.The testing samples had been pre-oxidized at 1100℃for 10 hours,they were kept at 1100℃,1150℃,1200℃and 1250℃for 10 hours after applying CMAS deposits with the same areal density.The destruction effect of CMAS on the oxide films on the surface of the substrate and bond coating was systematically analyzed at different temperatures.XRD,SEM and EDS were applied to illustrate that when the temperature was lower than 1150℃,CMAS deposits mainly affect the adhesion and thermal stress of the oxide films and lead to the peeling of oxide films during cooling;when the temperature was higher than 1150℃,CMAS deposits partially melt and penetrate into the inner part of oxide films,causing the oxide films to crack and dissolve,accelerating the damage of the substrate.
作者
由晓明
邹晗
何箐
Xiaoming You;Han Zou;Qing He(Surface Engineering Research Institute,Chinese Academy of Agricultural Mechanization Sciences,Beijing 100083;Beijing Jinlunkuntian Special Machine Co Ltd,Beijing 100083)
出处
《热喷涂技术》
2020年第2期22-29,10,共9页
Thermal Spray Technology
基金
国家科技重大专项(2017-Ⅶ-0007-0100)。
