Preparation of nanostructured Gd 2 Zr 2 O 7 -LaPO 4 thermal barrier coatings and their calcium-magnesium-alumina-silicate (CMAS) resistance

Li, Mingzhu; Cheng, Yuxiang; Guo, Liu; Zhang, Yuchen; Zhang, Chenglong; He, Sixian; Sun, Wei; Ye, Fuxing

doi:10.1016/j.jeurceramsoc.2017.03.069

Cited by 57 publications

(7 citation statements)

References 45 publications

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“…Two different ways to produce CMAS are found in the literature. In the former, the components are mixed in appropriate proportions and applied to the surface of the samples [16] [22] [23] [24] [25]. In the second, after mixing the components, a heat treatment is done before applying the material to the samples.…”

Section: Wettabilitymentioning

confidence: 99%

Study on the Attack of Molten Silicates on Plasma-Sprayed Thermal Barrier Coatings

Martins,

Friehe,

Silva

et al. 2023

JMMCE

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Thermal barrier coating (TBC) revolutionized the industry by allowing higher operating temperatures for equipment, such as gas turbines in the aeronautical industry. However, at high temperatures, the TBC is exposed to the attack of molten silicates, known as CMAS (Calcium-Magnesium-Alumino-Silicate), which are particles from the environment that infiltrate the TBC, causing delamination. In this study, samples coated with TBC by thermal spray and covered with CMAS were evaluated at temperatures of 1200˚C and 1250˚C. For each temperature, exposure times of 1 h and 5 h were used. Samples with longer exposure time had a considerable volume increase. The main contribution of this work was to demonstrate the non-wettability of the CMAS, even in the 5-h heat treatments, which prevented its infiltration in the deeper regions. The conditions to guarantee the formation of the silicate and its consequent wettability are also discussed.

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Section: Wettabilitymentioning

confidence: 99%

Study on the Attack of Molten Silicates on Plasma-Sprayed Thermal Barrier Coatings

Martins,

Friehe,

Silva

et al. 2023

JMMCE

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“…One could find melted splats (smooth zones), semi-melted particles, cracks, and pores on the coating surface, which are typical characteristics of APS coatings. During the plasma spraying process, coatings are exposed to large tensile stresses due to a rapid cooling rate, which causes some micro-cracks [30]. Cracks can improve the stress tolerance, which benefits the thermal shock performance of coatings.…”

Section: Characterizationsmentioning

confidence: 99%

Microstructure modification of Y2O3 stabilized ZrO2 thermal barrier coatings by laser glazing and the effects on the hot corrosion resistance

et al. 2020

Self Cite

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Y 2 O 3 stabilized ZrO 2 (YSZ) thermal barrier coatings (TBCs) are prone to hot corrosion by molten salts. In this study, the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance. By optimizing the laser parameters, a ~18 μm smooth glazed layer with some vertical cracks was produced on the coating surfaces. The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000 ℃ for 4 h in V 2 O 5 molten salt, and the results revealed that the modified one had improved corrosion resistance. After hot corrosion, the glazed layer kept structural integrity, with little evidence of dissolution. However, the vertical cracks in the glazed layer acted as the paths for molten salt penetration, accelerating the corrosion of the non-modified coating. Further optimization of the glazed layer is needed in the future work.

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“…Another type of microstructure explored for CMAS-resistant TBCs has been the nanostructuring approach, the high surface area of grains would be expected to promote enhanced crystallisation kinetics. Li et al [133] plasma sprayed nanostructured coatings consisting of 30 mol-% LaPO 4 doped Gd 2 Zr 2 O 7 . Coatings were exposed to a synthetic CMAS at 1250°C for up to 8 h. After 1 h exposure a reaction bilayer develops, where the first layer consisted of a Gd-La-P apatite, and the surface layer consisted of Gd-La-P based apatites, anorthites, spinels, and tetragonal ZrO 2 phases.…”

Section: Isothermal Testing Of Tbcsmentioning

confidence: 99%

Calcia–magnesia–alumina–silicate (CMAS) attack mechanisms and roadmap towards Sandphobic thermal and environmental barrier coatings

Nieto

Agrawal

Bravo

et al. 2020

International Materials Reviews

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This review critically examines the current understanding of calcia-magnesia-aluminasilicate (CMAS) degradation mechanisms and mitigation approaches in thermal and environmental barrier coatings. First, the review introduces case studies of field returned engine components exposed to CMAS attack, followed by fundamental aspects of CMASinduced degradation. Understanding CMAS adhesion, infiltration, spallation mechanics, and thermochemical attack mechanisms is crucial to designing materials approaches to mitigate CMAS attack. CMAS mitigation strategies have focused on reactive approaches aimed at crystallising molten CMAS at the earliest stage possible to inhibit infiltration. Promising approaches are presented, starting with fundamental reaction kinetics studies, followed by the effects of microstructure in actual coatings systems. Salient results on coating systems tested in various burner rigs and a full engine test are presented to benchmark the success of various mitigation strategies. Lastly, several key future research areas are presented in order to provide a roadmap towards 'sandphobic' thermal and environmental barrier systems.

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Preparation of nanostructured Gd 2 Zr 2 O 7 -LaPO 4 thermal barrier coatings and their calcium-magnesium-alumina-silicate (CMAS) resistance

Cited by 57 publications

References 45 publications

Study on the Attack of Molten Silicates on Plasma-Sprayed Thermal Barrier Coatings

Study on the Attack of Molten Silicates on Plasma-Sprayed Thermal Barrier Coatings

Microstructure modification of Y2O3 stabilized ZrO2 thermal barrier coatings by laser glazing and the effects on the hot corrosion resistance

Calcia–magnesia–alumina–silicate (CMAS) attack mechanisms and roadmap towards Sandphobic thermal and environmental barrier coatings

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