Phase-structures, thermophysical properties of Sm3Ce7Ta2O23.5 and Gd3Ce7Ta2O23.5 oxides for thermal barrier coating applications

Environmental sediments mainly consisting of CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) corrosion are a serious threat to thermal barrier coatings (TBCs), in which Fe element is usually ignored. Gd 2 Zr 2 O 7 TBCs are famous for their excellent CMAS resistance. In this study, the characteristics of Fe-containing environmental sediments (CMAS-Fe) and their corrosiveness to Gd 2 Zr 2 O 7 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 Gd 2 Zr 2 O 7 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, ZrO 2 , 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 Gd 2 Zr 2 O 7 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 Gd 2 Zr 2 O 7 coatings had a large consumption in the thickness, degrading the coating performance. Therefore, the Gd 2 Zr 2 O 7 coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.

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Research Progresses on Ceramic Materials of Thermal Barrier Coatings on Gas Turbine

Zhao

et al. 2021

Coatings

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Thermal barrier coatings (TBCs) play a vitally important role in protecting the hot parts of a gas turbine from high temperature and corrosion effectively. More and more attention has been paid to the performance modification of ZrO2-based ceramics and seeking for new ceramic materials to meet requirements of gas turbine TBCs. The working principle, merits, and demerits of main technologies for coating preparation are elaborated in this paper, and the properties of new ceramic materials are reviewed. It is found that the thermal conductivity, thermal stability, mechanical properties, and other performances of traditional ZrO2-based ceramics could be improved effectively by doping modification. The emphases for new ceramic materials research were put on pyrochlores, magnetoplumbites, rare-earth tantalates, etc. Rare-earth tantalates with great potentials as new top ceramic materials were described in detail. In the end, the development directions of advanced top ceramic coatings, combining doping modification with preparation technology to regulate and control structure property of high-performance ceramic material, were put forward.

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Phase-structures, thermophysical properties of Sm3Ce7Ta2O23.5 and Gd3Ce7Ta2O23.5 oxides for thermal barrier coating applications

Cited by 3 publications

References 37 publications

New Materials for Thermal Barrier Coatings: Design, Manufacturing and Performance

New Materials for Thermal Barrier Coatings: Design, Manufacturing and Performance

Corrosion behavior of Gd ₂Zr ₂O ₇ thermal barrier coatings under Fe-containing environmental sediment attack

Research Progresses on Ceramic Materials of Thermal Barrier Coatings on Gas Turbine

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Phase-structures, thermophysical properties of Sm3Ce7Ta2O23.5 and Gd3Ce7Ta2O23.5 oxides for thermal barrier coating applications

Cited by 3 publications

References 37 publications

New Materials for Thermal Barrier Coatings: Design, Manufacturing and Performance

New Materials for Thermal Barrier Coatings: Design, Manufacturing and Performance

Corrosion behavior of Gd 2Zr 2O 7 thermal barrier coatings under Fe-containing environmental sediment attack

Research Progresses on Ceramic Materials of Thermal Barrier Coatings on Gas Turbine

Contact Info

Product

Resources

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Corrosion behavior of Gd ₂Zr ₂O ₇ thermal barrier coatings under Fe-containing environmental sediment attack