Investigation of three steps of hot corrosion process in Y2O3 stabilized ZrO2 coatings including nano zones

Phase transformation of tetragonal ZrO2 to monoclinic phase and also increment of bond coat oxidation kinetic（TGO thickening） can substantially restrict the life time of thermal barrier coating systems（TBCs）. So, nanostructured and conventional Y2O3 stabilized ZrO2 coatings were evaluated in fused V...

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Published inJournal of rare earths Vol. 32; no. 10; pp. 989 - 1002
Main Authors Daroonparvar, Mohammadreza, Yajid, Muhamad Azizi Mat, Yusof, Noordin Mohd, Bakhsheshi-Rad, Hamid Reza, Hamzah, Esah, Nazoktabar, Mohsen
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.10.2014
Subjects
diffusion
nano zones
oxidation
plasma deposition
rare earths
YVO4晶体
ZrO2涂层
微观结构特征
氧化锆涂层
热障涂层
稳定氧化锆
纳米Y2O3
腐蚀工艺
oxidation
plasma deposition
diffusion
nano zones
rare earths
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Summary:Phase transformation of tetragonal ZrO2 to monoclinic phase and also increment of bond coat oxidation kinetic（TGO thickening） can substantially restrict the life time of thermal barrier coating systems（TBCs）. So, nanostructured and conventional Y2O3 stabilized ZrO2 coatings were evaluated in fused V2O5-Na2SO4 salts during thermal exposure in air. Microstructural characterization showed lower hot corrosion products（monoclinic zirconia, YVO4 crystals） formation and reduction of TGO thickness in thermal barrier coating system consisting of nanostructured Y2O3 stabilized ZrO2（YSZ） top coat. It was found that inhomogeneities, pores and micro-cracks played a principal role in the molten salts infiltration into the YSZ coating during three steps of hot corrosion process. In the nanostructured YSZ coating with tri-model structure, nano zones which surrounded by fully molten parts could fill the aforementioned defects and could act as barrier for the oxygen and corrosive molten salts penetration into the TBC.
Bibliography:11-2788/TF
nano zones; plasma deposition; diffusion; oxidation; rare earths
Mohammadreza Daroonparvar , Muhamad Azizi Mat Yajid, Noordin Mohd Yusof, Harnid Reza BakhsheshiRad, Esah Hamzah, Mohsen Nazoktabar（1. Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia, 2. Department of Mechanical Engineering, Faculty of Engineering, Roudehen Islamic Azad University, 189 Roudehen, Tehran 021, Iran）
Phase transformation of tetragonal ZrO2 to monoclinic phase and also increment of bond coat oxidation kinetic（TGO thickening） can substantially restrict the life time of thermal barrier coating systems（TBCs）. So, nanostructured and conventional Y2O3 stabilized ZrO2 coatings were evaluated in fused V2O5-Na2SO4 salts during thermal exposure in air. Microstructural characterization showed lower hot corrosion products（monoclinic zirconia, YVO4 crystals） formation and reduction of TGO thickness in thermal barrier coating system consisting of nanostructured Y2O3 stabilized ZrO2（YSZ） top coat. It was found that inhomogeneities, pores and micro-cracks played a principal role in the molten salts infiltration into the YSZ coating during three steps of hot corrosion process. In the nanostructured YSZ coating with tri-model structure, nano zones which surrounded by fully molten parts could fill the aforementioned defects and could act as barrier for the oxygen and corrosive molten salts penetration into the TBC.
ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(14)60173-3