冷喷涂NiCoCrAlY涂层的组织结构特征与抗氧化性能研究

Microstructure Characteristics and Oxidation Resistance of Cold-sprayed NiCoCrAlY Coating

利用低压冷喷涂技术制备了Ni Co Cr Al Y涂层,采用SEM、XRD分析了涂层的组织结构特征,利用静态氧化实验研究了抗氧化性能。结果表明,冷喷涂Ni Co Cr Al Y涂层含氧量为0.25%,涂层孔隙率小于0.92%;冷喷涂过程中,喷涂粉末材料发生了相变,由γ-Matrix Ni-Co-Cr固溶体和β-(Ni,Co)Al金属间化合物双相结构转变为γ-Matrix单相结构,同时涂层中含大量纳米晶;经1 050℃氧化400 h后,冷喷涂Ni Co Cr Al Y涂层表面除α-Al2O3外还生成了少量尖晶石,氧化膜未见明显脱落,厚度为2.85±0.12μm,预计还有较长的抗氧化寿命。

A NiCoCrAlY coating was prepared by low-pressure cold spray technology. After deposi-tion,the microstructure of as-sprayed coating was characterized by SEM and XRD. The oxidation re-sistance of as-sprayed coating was investigated by static oxidation experiment. The results show that the as-sprayed coating presents a dense structure with low oxygen content （0. 25 % mass fraction） and low porosity （less than 0. 92% volume fraction）. In the process of cold spraying,the powder ma-terial has a phase transition,which is transformed from theγ-Matrix Ni-Co-Cr andβ-（ Ni,Co） Al in-to a single phase structure of γ-Matrix. Furthermore,the as-spayed coating contained a large amount of nanocrystals. After oxidation for 400 h at 1 050 ℃,a dense and continuous TGO with a thickness of 2. 85 ＆#177; 0. 12 μm,mainly composed ofα-Al2 O3 ,was formed in the surface of as-sprayed. The spal-ling of TGO did not occur. The NiCoCrAlY Coating was expected to have a longer oxidation life.