镍钴基高温合金的氧化动力学与界面结合性能

Oxidation kinetics and interfacial bonding properties of Ni-Co based superalloys

采用XRD,SEM和静态增重法等研究镍钴基GH783高温合金的氧化行为和氧化过程动力学,并通过纳米划痕试验对膜基结合性能进行表征。研究结果表明:合金在500~700℃没有生成氧化膜,在800℃时开始生成由Fe2O3和少量Fe3O4组成的氧化层,900℃时生成的氧化膜中Fe3O4含量增多;合金在800℃氧化100h后,合金表面生成致密的Fe2O3-Fe3O4复合物氧化膜,膜厚约为15μm;合金的氧化动力学曲线符合抛物线规律,抛物线速度常数为3.44×10^-5mg^2/(cm^4·h);随着氧化时间增长,氧化膜与基体的界面结合性能愈趋良好,于800℃氧化100h后膜基结合力达8.92N。

The oxidation behavior and oxidation kinetics of Ni-Co based superalloy were studied by XRD,SEM and the thermogravimetric analysis method.The adhesion strength of the films was characterized by nanoscratch test.The results show that the oxide film is not formed at 500-700 ℃,and an oxide layer is composed of Fe2O3 and a small amount of Fe3O4 forms at 800 ℃.Moreover,the content of Fe3O4 increases rapidly in the oxide film formed at 900 ℃.After oxidized at 800 ℃ for 100 h,a dense oxide film of Fe2O3-Fe3O4 with the film thickness of about 15 μm is formed on the surface of the alloy.The oxidation kinetics curve of the alloy obeys the parabolic law and the speed constant is 3.44× 10^-5mg^2/(cm^4·h).With the increase of oxidation time,the interface bonding performance between the oxide film and the matrix gets better and better.The film/substrate bonding force reaches 8.92 N after oxidation at 800 ℃ for 100 h.