材料期刊网

通过对有/无 Ni11Co26Cr6Al0.5Y涂层镍基合金在1000℃进行氧化动力学曲线测定，及组织结构观察，研究了 Ni11Co26Cr6Al0.5Y涂层对镍基合金高温氧化行为的影响。结果表明：高温氧化期间，合金发生外氧化和内氧化，外氧化层由 NiO、NiCrO4、CoWO4构成，中间氧化物由TiO2、Al2 O3、NiWO4构成，中间层氧化物层抑制了基体中 Al元素向外扩散，形成平直连续的 Al2 O3内氧化物层；合金氧化动力学曲线呈现起伏波动的特征。镍基合金经溅射 Ni11Co26Cr6Al0.5Y涂层，可有效改善合金的抗氧化性能；涂层的氧化动力学曲线仅在氧化初期有轻微增重而后趋于平稳，遵循抛物线规律，其形成的 Al2 O3氧化膜未发生明显剥落，仅在涂层内及近涂层/基体界面区域存在少量 Al2 O3内氧化物。

By mean of observation of the microstructure and measurement of the isothermal oxidation mass-change curves, the high temperature oxidation characteristic of a nickel-based superalloy with and without Ni11Co26Cr6Al0.5Y coating was investigated.The results showed that obvious oxidation and internal oxidation oc-curred.There were three layers in the oxidation region of the superalloy without coating.The outer layer consisted of NiO,NiCrO4 ,CoWO4 phases,the middle layer consisted of TiO2 ,Al2 O3 ,NiWO4 phases,and internal oxidation la-yer consisted of Al2 O3 .Al2 O3 phase with layer-like feature was beneath middle layers,which could restrain the diffu-sion of the element Al and decrease the oxidation rate of the alloy.The sputtered Ni11Co26Cr6Al0.5Y coating may ef-fectively improve the oxidation resistance of the alloy.The kinetic curve of the coated alloy displayed a smaller mass change because the Al2 O3 formed on the surface could hardly peel off,and j ust a few internal oxidation (Al2 O3 )ap-peared near the interface of coating/matrix and inside the coating.