基体表面喷丸处理对纳米晶涂层循环氧化行为的影响

Effect of Shot Peening of Substrate Surface on Cyclic Oxidation Behavior of Sputtered Nanocrystalline Coating

采用磁控溅射技术分别在抛光和喷丸处理后的镍基单晶高温合金基体上制备纳米晶涂层,并研究了2种涂层在1100℃下的循环氧化行为。采用XRD、SEM和EDS表征涂层的物相组成和微观形貌。结果表明,1100℃下2种纳米晶涂层的循环氧化增重趋势基本一致,均能在表面形成致密的氧化膜,展现出优异的抗氧化性能。2种纳米晶涂层与基体的界面及界面附近区域的微观形貌演变有所差异,随着氧化实验的进行,在抛光基体/涂层界面处涂层一侧观察到γ’相的持续形成;在喷丸基体/涂层界面处涂层一侧未发现此现象,而在基体一侧观察到γ’相不断长大。

In addition to changing the surface roughness of the superalloy,the substrate surface treatment can also modify the microstructure of the surface,which affects the high-temperature oxidation behavior of the high-temperature protective coating.However,there are few reports about the effect of superalloy surface treatment on the oxidation behavior of nanocrystalline coatings.In this work,nanocrystalline coatings were sputtered on the nickel-based single crystal superalloy after two different surface treatments of polishing and shot peening,and their cyclic oxidation behavior at 1100oC was investigated.The phase composition and microstructure of nanocrystalline coatings were characterized by SEM,XRD,and EDS.The results indicated that the cyclic oxidation kinetics of both nanocrystalline coatings at 1100oC were similar.A dense oxide film could be formed on the surface of nanocrystalline coatings,showing excellent oxidation resistance.However,the microstructure evolution of the interface between the nanocrystalline coating and shot-peened superalloy substrate differed from that between the nanocrystalline coating and polished superalloy substrate.The sustained formation of theγ′phase in the nanocrystalline coating near the polished substrate/coating interface was observed during high-temperature oxidation.This phenomenon was not found at the nanocrystalline coating near the shot peened substrate/coating interface,while the continuous growth of theγ'phase was observed at the substrate.