电子束熔凝NiCoCrAlY涂层的高温氧化行为分析

High temperature oxidation behaviour of NiCoCrAlY coating produced by electron beam technology

在GH140高温合金钢基体表面采用磁控溅射沉积NiCoCrAlY涂层,并用电子束进行熔凝处理。分析结果表明,电子束熔凝使NiCoCrAlY涂层与基体形成组分梯度变化的混合层,提高了涂层与基体的结合程度。涂层经1000℃和1100℃,10h的对比氧化试验,结果表明,在1000℃时,Cr扩散至表面,由于CrO3的挥发而迅速损耗,但Y的存在,在一定程度上减缓了Cr的损失速度。1100℃时起抗氧化作用的主要来自Al、Ti、Si、Mn等,Al的内氧化抑止了Al的外扩散。

GH140 substrates were coated with NiCoCrAlY by magnetron sputtering and subsequently processed by electron beam.The result shows that mixed transition layer with composition gradient between coatings and the substrates has been formed, which is benefical to adhesion of coatings to substrates. The coatings were oxidized at 1 000 ℃ and 1 100 ℃ for 10 h, respectively.The results based on XRD, SEM-EDAX show that, at 1 000 ℃, Cr diffuses to the surface and loses due to the volatilization of CrO3, but the Y on the surface can decrease such a loss. While, at 1 100 ℃ , oxidation resistance of the coatings results from Al,Ti,Si,Mn etc, and inner oxidation of Al inhibits its extradiffusion.