用低压等离子喷涂(LPPS)和爆炸喷涂(DS)方法，在镍基单晶 高温合金上制备NiCrAlY涂层.涂层在1050℃恒温氧化300 h，借助XRD、SEM和EDS，对涂层表 面氧化膜进行分析，检测其恒温抗氧化能力.结果表明两种涂层表面均能形成Al2O3保护 膜，二者的氧化动力学曲线均符合抛物线规律.DS涂层的微孔内含残留气体，涂层内氧化严 重，氧化增重大，氧化速率常数近似LPPS涂层的二倍.氧化300 h后，DS涂层表面边角处氧 化膜有少量剥落，而LPPS涂层保持完好，只在个别突起处有微小开裂.
NiCrAlY coatings,respectively prepared by detonatio n spray (DS)and low-pressure plasma spray (LPPS),were deposited on a single crys tal Ni-base superalloy.Specimens were isothermally oxidized at 1050℃ for 300h.B y means of XRD,SEM and EDS,oxidation behaviors of the coatings were analyzed.The results showed that Al2O3 protective scale was formed on both DS NiCrAlY co ating and LPPS NiCrAlY coating.Their oxidation kinetics obeyed the parabolic law .Since DS coating entrapped the air,its internal oxide appeared earlier and much more than that of LPPS coating,which lead to a relatively rapid weight gain.The oxidation rate constant of DS NiCrAlY coating is about two times of that of LPP S coating.Some spallation occurred on the oxide scale of DS coating after oxidiz ed for 300 hours,while the oxide scale of LPPS coating kept almost intact except for a few microcracks on the protuberances.
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