Influence of Sputtered Nanocrystalline Coating on Oxidation and Hot Corrosion of a Nickel-based Superalloy M951
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2014年第9期
论文作者：Xinyue Wang Li Xin Fuhui Wang Shenglong Zhu Hua Wei Xiaolan Wang
文章页码：867 - 877
摘 要：The isothermal and cyclic oxidation behaviors in air and hot corrosion behaviors in Na2SO4t 25 wt%K2SO4salt of M951 cast superalloy and a sputtered nanocrystalline coating of the same material were studied.Scanning electron microscopy,energy dispersive X-ray spectroscope,X-ray diffraction,and transmission electron microscopy were employed to examine the morphologies and phase composition of the M951 alloy and nanocrystalline coating before and after oxidation and hot corrosion.The as-sputtered nanocrystalline layer has a homogeneous g phase structure of very fine grain size（30e200 nm）with the preferential growth texture of（111）parallel to the interface.Adherent Al2O3rich oxide scale formed on the cast M951 alloy and its sputtered coating after isothermal oxidation at 900 and 1000 C.However,when being isothermal oxidized at 1100 C and cyclic oxidized at 1000 C,the oxide scale formed on the cast alloy was a mixture of NiO,NiAl2O4,Al2O3and Nb2O5and spalled seriously,while that formed on the sputtered coating mainly consisted of Al2O3and was very adherent.Nanocrystallization promoted rapid formation of Al2O3scale during the early stage of oxidation and enhanced the adhesion of the oxide scale,thus improved the oxidation resistance of the substrate alloy.Serious corrosion occurred for the cast alloy.The sputtered nanocrystalline coating apparently improved the hot corrosion resistance of the cast alloy in the mixed sulfate by the formation of a continuous Al2O3and Cr2O3mixed oxide layer on the surface of the coating,and the preoxidation treatment of the coating led to an even better effect.
Xinyue Wang1,2，Li Xin2，Fuhui Wang2，Shenglong Zhu2，Hua Wei2，Xiaolan Wang2
1. School of Materials and Metallurgy, Northeastern University2. State Key Laboratory for Corrosion and Protection, Institute of Metal Research,Chinese Academy of Sciences
摘 要：The isothermal and cyclic oxidation behaviors in air and hot corrosion behaviors in Na2SO4t 25 wt%K2SO4salt of M951 cast superalloy and a sputtered nanocrystalline coating of the same material were studied.Scanning electron microscopy,energy dispersive X-ray spectroscope,X-ray diffraction,and transmission electron microscopy were employed to examine the morphologies and phase composition of the M951 alloy and nanocrystalline coating before and after oxidation and hot corrosion.The as-sputtered nanocrystalline layer has a homogeneous g phase structure of very fine grain size（30e200 nm）with the preferential growth texture of（111）parallel to the interface.Adherent Al2O3rich oxide scale formed on the cast M951 alloy and its sputtered coating after isothermal oxidation at 900 and 1000 C.However,when being isothermal oxidized at 1100 C and cyclic oxidized at 1000 C,the oxide scale formed on the cast alloy was a mixture of NiO,NiAl2O4,Al2O3and Nb2O5and spalled seriously,while that formed on the sputtered coating mainly consisted of Al2O3and was very adherent.Nanocrystallization promoted rapid formation of Al2O3scale during the early stage of oxidation and enhanced the adhesion of the oxide scale,thus improved the oxidation resistance of the substrate alloy.Serious corrosion occurred for the cast alloy.The sputtered nanocrystalline coating apparently improved the hot corrosion resistance of the cast alloy in the mixed sulfate by the formation of a continuous Al2O3and Cr2O3mixed oxide layer on the surface of the coating,and the preoxidation treatment of the coating led to an even better effect.
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