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5408 |
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Thermal cycling behavior of plasma sprayed yttria partially-stabilized zirconia thick thermal barrier coating |
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Xinghua Zhong* / Shanghai Institute of Ceramics, Chinese Academy of Sciences, P.R. China Jinxing Ni/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Huayu Zhao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Chenguang Liu/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Yin Zhuang/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Shunyan Tao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China |
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The present paper focused on evaluating the cyclic thermal shock performance of the thick thermal barrier coatings (TBCs) plasma sprayed with nano-agglomerated 7wt% Y2O3 partially stabilized ZrO2 (7YSZ). The 7YSZ coating in thickness of approximately 700 microns was deposited on superalloy substrate with a 150 micron-thick CoNiCrAlY bond coat. The vertically segmented cracks were observed in the YSZ coatings. The phase analysis shows that the coating crystallized in non-transformable tetragonal phase of zirconia. The thermal cycling test of the YSZ coatings was carried out on a burner rig with propane-oxygen flame which heated the coating surface at temperature of 1523 K, followed by quenching to temperature below 423 K by compressed air. The results obtained shows that the YSZ coatings performs longer thermal shock life relative to the atmospheric plasma sprayed (APS) counterparts fabricated with conventional YSZ feedstock under the same test conditions, which is probably attributed to the improvement in strain tolerance through the vertically segmented cracks therein. The failure behaviour of the coatings deposited with nano-agglomerated YSZ is different from that of the above counterparts, which is supposed to be related to the special microstructure. |