等离子喷涂–物理气相沉积7YSZ热障涂层沉积机理及其CMAS腐蚀失效机制  

Deposition and CMAS Corrosion Mechanism of 7YSZ Thermal Barrier Coatings Prepared by Plasma Spray-Physical Vapor Deposition

作　　者：张小锋[1,2] 周克崧[1,2] 宋进兵[2] 邓春明[2] 牛少鹏[1,2] 邓子谦[2] 

机构地区：[1]华南理工大学材料科学与工程学院,广州510640 [2]广州有色金属研究院新材料研究所,广州510650

出　　处：《无机材料学报》2015年第3期287-293,共7页Journal of Inorganic Materials

基　　金：国家973计划(2012CB625100);国家863计划(2012AA03A512)~~

摘　　要：采用等离子喷涂–物理气相沉积(PS-PVD)以团聚烧结的ZrO2-7wt%Y2O3(7YSZ)为原料,在850℃基体温度下制备了具有柱状结构的热障涂层,并通过场发射–扫描电镜(FE-SEM)分析了柱状涂层的显微结构。此外,基于原子聚集理论研究了PS-PVD中7YSZ气相分子在基体上的形核与生长过程,并分析了高温基体下7YSZ柱状涂层的沉积机理。另外,在1200℃下考察了7YSZ柱状涂层的CaO-MgO-Al2O3-SiO2(CMAS)腐蚀性能并探讨了其失效机制。结果表明,在高温下7YSZ气相分子首先吸附在基体上,通过扩散迁移形成分子团并吸附在基体表面上,然后分子团再与其它吸附分子碰撞结合形成临界晶核,临界晶核捕获其它吸附分子进一步长大形成晶核小岛,此后依次经过岛状、联并、沟道、连续这四个阶段最终形成柱状涂层。高温下CMAS熔融并在毛细管力的作用下沿着柱状涂层孔隙往深度方向渗透并与涂层发生热化学反应使涂层热物性能发生变化,最终在热化学与热机械的相互作用下使涂层内产生平行于表面的横向裂纹,并层离失效。Using agglomerated and sintered ZrO2-7wt%Y203 （7YSZ） powders as raw materials, columnar thermal barrier coatings （TBCs） were prepared by plasma spray-physical vapor deposition （PS-PVD） at substrate tempera- ture of 850℃. The microstructures of columnar coating were analyzed by field emission-scanning electron micro- scope （FE-SEM）. Based on the theory of atoms together, the formation and growth process of 7YSZ nucleus were investigated and the deposition mechanism of columnar coating was also analyzed. Besides, under the temperature of 1200 ℃, the CMAS （CaO-MgO-AI203-SiO2） corrosion of columnar 7YSZ coating was examined and its failure mechanism was also discussed. During the deposition process of columnar 7YSZ coating, the 7YSZ gas molecules were firstly absorbed on substrate, then through diffusion and migration, the critical nucleus formed rapidly. Besides, the critical nucleus further grew up forming crystal island by absorbing other molecules. Then after following foursteps of island formation, union formation, channel formation and continuation, the columnar coating formed even- tually. When above melting temperature, the CMAS could penetrate into porous columnar coating by capillary force and react with the 7YSZ coating. Finally, the cracks appeared in the coating due to thermochemical and thermome- chanical interaction

关 键 词：等离子喷涂–物理气相沉积 沉积机理 CMAS腐蚀 腐蚀机制 

分 类 号：TQ174[化学工程—陶瓷工业]