@article{Guo2024, 
author = {Lei Guo and Yanyan Li and Kai Yan},
title = {Corrosion behavior of Gd2Zr2O7 thermal barrier coatings under Fe-containing environmental sediment attack},
year = {2024},
journal = {Journal of Advanced Ceramics},
volume = {13},
number = {4},
pages = {447-462},
keywords = {thermal barrier coatings (TBCs), corrosion resistance, reaction layer, Gd2Zr2O7, Fe-containing CaO–MgO–Al2O3–SiO2 (CMAS)},
url = {https://www.sciopen.com/article/10.26599/JAC.2024.9220867},
doi = {10.26599/JAC.2024.9220867},
abstract = {Environmental sediments mainly consisting of CaO–MgO–Al2O3–SiO2 (CMAS) corrosion are a serious threat to thermal barrier coatings (TBCs), in which Fe element is usually ignored. Gd2Zr2O7 TBCs are famous for their excellent CMAS resistance. In this study, the characteristics of Fe-containing environmental sediments (CMAS-Fe) and their corrosiveness to Gd2Zr2O7 coatings were investigated. Four types of CMAS-Fe glass with different Fe contents were fabricated. Their melting points were measured to be 1322–1344 ℃, and the high-temperature viscosity showed a decreasing trend with increasing Fe contents. The corrosion behavior of four types of CMAS-Fe to Gd2Zr2O7 coatings at 1350 ℃ was investigated. At the initial corrosion stage (0.1 h), anorthite was precipitated in CMAS-Fe with a high Ca : Si ratio, while Fe-garnet was formed in the melt with the highest Fe content. Prolonging the corrosion time resulted in the formation of a reaction layer, which exhibited an interpenetrating network composed of Gd-oxyapatite, ZrO2, and residual CMAS-Fe. Some spinel was precipitated within the reaction layer. After 1 h or even longer time, the reaction layers tended to be stable and compact, which had comparable hardness and fracture toughness to those of Gd2Zr2O7 coatings. Under the cyclic CMAS-Fe attack, the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration, resulting in the continuous growth of the reaction layer. As a result, the Gd2Zr2O7 coatings had a large consumption in the thickness, degrading the coating performance. Therefore, the Gd2Zr2O7 coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.}
}