Effects of bond coat and top coat（including nano zones） structures on morphology and type of formed transient stage oxides at pre-heat treated nano NiCrAlY/nano ZrO2-8%Y2O3 interface during oxidation
来源期刊：JOURNAL OF RARE EARTHS2015年第9期
论文作者：Mohammadreza Daroonparvar
文章页码：983 - 994
摘 要：Bond coat geometry is able to significantly influence thermally grown oxide（TGO） layer formation and growth in thermal barrier coating systems at the onset of oxidation. Moreover, nanostructured yttria stabilized zirconia coating with three model structure（including nano zones） could reduce oxygen partial pressure to the formation pressure of continues alumina oxide scale which was able to protect the substrate from extra oxidation and corrosion. Thus, nano Ni Cr Al Y/nano YSZ and normal Ni Cr Al Y/nano YSZ coatings were prepared by air plasma spray method and then evaluated by high temperature oxidation test at 1000 °C for 160 h. As-sprayed samples were also pre-oxidized at 1000 °C for 48 h and then examined by electrochemical polarization test. The corrosion rate of the pre-oxidized nano Ni Cr Al Y/nano YSZ coating was estimated to be the lowest compared to that of the other samples. It might be related to the formation of continues alumina layer on the nano Ni Cr Al Y at the onset of oxidation. This continuous layer could reduce the penetration of the aggressive solution into the Ni Cr Al Y coating and acted as a protective layer（with the lowest anodic current density）. This layer also lessened TGO growth rate at the stages II and III of the growth.
Mohammadreza Daroonparvar
Department of Materials Engineering, Faculty of Engineering, Azad University,Roudehen Branch
摘 要：Bond coat geometry is able to significantly influence thermally grown oxide（TGO） layer formation and growth in thermal barrier coating systems at the onset of oxidation. Moreover, nanostructured yttria stabilized zirconia coating with three model structure（including nano zones） could reduce oxygen partial pressure to the formation pressure of continues alumina oxide scale which was able to protect the substrate from extra oxidation and corrosion. Thus, nano Ni Cr Al Y/nano YSZ and normal Ni Cr Al Y/nano YSZ coatings were prepared by air plasma spray method and then evaluated by high temperature oxidation test at 1000 °C for 160 h. As-sprayed samples were also pre-oxidized at 1000 °C for 48 h and then examined by electrochemical polarization test. The corrosion rate of the pre-oxidized nano Ni Cr Al Y/nano YSZ coating was estimated to be the lowest compared to that of the other samples. It might be related to the formation of continues alumina layer on the nano Ni Cr Al Y at the onset of oxidation. This continuous layer could reduce the penetration of the aggressive solution into the Ni Cr Al Y coating and acted as a protective layer（with the lowest anodic current density）. This layer also lessened TGO growth rate at the stages II and III of the growth.
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