电弧离子镀NiCoCrAlY涂层的组织结构及初期氧化

MICROSTRUCTURE AND INITIAL STAGE OXIDATION OF NiCoCrAlY COATINGS DEPOSITED BY ARC ION PLATING TECHNIQUE

采用XRD,SEM,TEM和光激发荧光谱等技术对电弧离子镀制备的NiCoCrAlY涂层的组织结构和初期氧化的机理进行了研究.结果表明,电弧离子镀方法沉积的NiCoCrAlY涂层具有纳米晶体结构,呈明显的层状生长.真空退火后涂层内的层状结构消失,涂层组织更致密,晶粒明显长大.有孪晶出现.涂层在真空退火后表面已经生成一层很薄的以α-Al2O3为主的氧化膜,在高温氧化过程中,涂层表面的亚稳态氧化物θ-Al2O3先增多,然后逐渐转变为稳态的α-Al2O3,并对其相关机理进行了探讨.

The microstructure of the NiCoCrAlY coatings deposited by arc ion plating （AIP） and its oxidation mechanism at initial stage were investigated by XRD, SEM, TEM and photostimulated luminescence spectroscopy （PSLS）. The results showed that as-deposited NiCoCrAlY coatings were composed of nano-grains and possessed apparent layered structure. After vacuum annealing, the layered microstructure disappeared and the coating became much denser. The nano-grains in the coatings became much larger and twinned grains appeared. In addition, a very thin oxide scale mainly of α-Al2O3 formed on the coating surface after annealing. In the subsequent initial oxidation stages, transient θ-Al2O3 increased and then turned into stable α-Al2O3. The related mechanism was also discussed.