空心阴极电弧镀NiCrAlY涂层的抗氧化性能

采用空心阴极电弧离子镀技术制备NiCrAlY涂层,研究涂层的高温抗氧化性能。结果表明涂层组织致密,与合金结合状态良好。电弧离子镀NiCrAlY涂层在1 100℃恒温氧化100h后增重只有2.22mg/cm2,在100次循环氧化后仍没有失重现象,其抗恒温氧化和抗循环氧化性能远优于成分相近的超音速火焰喷涂、爆炸喷涂和大气等离子喷涂的NiCrAlY涂层。电弧离子镀NiCrAlY涂层在恒温氧化和循环氧化过程中表面均形成了连续致密、粘附性的氧化铝保护膜。氧化膜没有翘起和剥落现象,涂层组织在氧化后仍然完整致密。热喷涂NiCrAlY涂层在上述氧化过程中则生成了保护性较差的Ni、Cr和Al混合氧化物,并发生了氧化膜剥落,同时有严重的内氧化现象。

Oxidation Resistance of the NiCrAlY Coating Prepared by Hollow Cathode Arc Ion Plating Technique

NiCrAlY coating was deposited by hollow cathode arc ion plating technique,and the oxidation resistance at 1 100 ℃ was studied.The results show that the coating is dense and well adhesive to the nickel-base superalloy substrate.The arc ion plated NiCrAlY coating just increases 2.22 mg/cm2 after isothermal oxidation for 100 h at 1 100 ℃ and loss no weight after 100 cycles of cyclic oxidation at 1 100 ℃,which makes it remarkably superior to high velocity oxygen-fuel,D-gun and air plasma sprayed NiCrAlY coatings with similar compositions concerning isothermal and cyclic oxidation resistance at 1 100 ℃.The dense,continuous and adherent alumina oxide scale develops on the arc ion plated coating surface during the isothermal or cyclic oxidation test at 1 100 ℃.In addition,no remarkable delamination and spallation is detected for the alumina scale formed on the arc ion plated NiCrAlY coating and the coating remains intact after oxidation at 1 100 ℃.On the contrary,the thermally spray NiCrAlY coatings suffer severe oxidation damage during tests and produce non-protective oxide consisting of nickel,chromium and aluminium.Moreover,the oxide films flake and the thermally sprayed coatings are susceptible to significant internal oxidation.