High-temperature oxidation performance of novel environmental barrier coating 50HfO2-50SiO2/YxYb(2−x)Si2O7 at 1475 °C

Zhang, Zhenya; Park, Youngjin; Kim, Do Hyun; Zhang, Xue; Ji, Xiaojuan; Park, Hunkwan; Zhang, Shihong; Byon, Eungsun; Koo, Bon Heun

doi:10.1016/j.jeurceramsoc.2022.10.082

Cited by 16 publications

(1 citation statement)

References 51 publications

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“…In recent decades, multilayered EBC systems have been widely studied for their ability to achieve excellent combinations of properties, including high volatilization and oxidation resistance, good thermomechanical compatibility, and strong bonding strength. The most promising system consists of a protective top layer of ytterbium silicate, which includes ytterbium monosilicate (Yb2SiO5, YbMS) and ytterbium disilicate (Yb2Si2O7, YbDS) [7,8]; an oxygen shielding intermediate layer, such as mullite (if required) [9][10][11]; and a bond layer, such as silicon, to enhance the adhesion strength and oxidation resistance of the substrate [12][13][14]. When operating in a high-temperature oxidative environment, oxidants penetrate the outer layers to reach the silicon surface, leading to the formation of a thermally grown SiO2 oxide layer (SiO2-TGO).…”

Section: Introductionmentioning

confidence: 99%

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

Dong,

Yang,

Chen

et al. 2024

Journal of Advanced Ceramics

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The lifetime of Si-based environmental barrier coatings (EBCs) is constrained by thermally grown SiO2 (SiO2-TGO), which can cause premature cracking and spalling. To address this issue, a new approach for surface modification using aluminum is proposed.The oxidation performance was examined in a 50 vol% H2O -50 vol% O2 environment at 1350 ℃ for up to 300 h. The results indicate that a dense ytterbium aluminum garnet (YbAG) layer was formed after modification, decreasing the porosity by 80%. Due to the elimination of fast diffusion channels and the low oxygen permeability of YbAG, aluminum modification significantly reduced the growth rate of SiO2-TGO by nearly two orders of magnitude. Consequently, its thickness decreased by more than 70% after 300 h J u s t A c c e p t e d 2 of exposure. A diffusion-controlled oxidation mechanism indicates that the modified dense surface is equivalent to an initial SiO2 layer with a specific thickness, causing a shift in the oxidation time and increasing the oxidation resistance. This research provides valuable insights for designing Si-based EBC with improved lifetimes.

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Section: Introductionmentioning

confidence: 99%

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

Dong,

Yang,

Chen

et al. 2024

Journal of Advanced Ceramics

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Environmental Barrier Coatings (EBCs) for Ceramic Matrix Composites

Zhou,

Guo

2023

Engineering Materials

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Thermal properties and calcium-magnesium-alumino-silicate (CMAS) interaction of novel γ-phase ytterbium-doped yttrium disilicate (γ-Y1.5Yb0.5Si2O7) environmental barrier coating material

Zhang,

Bai

et al. 2024

Adv Compos Hybrid Mater

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Rare-earth disilicates are promising candidates for thermal and environmental barrier coatings (TEBC) in gas turbines that safeguard SiCf/SiC ceramic matrix composites (CMCs) from thermal degradation and environmental attacks. Here, we report a systematic investigation on novel TEBC material, γ-Y1.5Yb0.5Si2O7. The γ-phase quarter molar ytterbium–doped yttrium disilicate exhibited low thermal conductivity (1.72 W·m−1·K−1 at 1200 °C) and reduced intrinsic thermal expansion (3.17 ± 0.22 × 10−6 K−1 up to 1000 °C), ensuring promisingly effective thermal insulation and minimized thermal stress with CMC substrates. Using density functional theory (DFT), the heat capacity of γ-Y1.5Yb0.5Si2O7 was predicted higher than that of undoped γ-Y2Si2O7. Comparing these predictions to results calculated using the Neumann–Kopp (NK) rule revealed only minor variations. A metastable CMAS interaction byproduct, cyclosilicate phase Ca3RE2(Si3O9)2, was identified based on energy dispersive X-ray spectrometer (EDS) and electron backscatter diffraction (EBSD) techniques, appearing at 1300 °C but disappearing at 1400 °C. The γ-Y1.5Yb0.5Si2O7 exhibited good CMAS resistance on both dense pellets and sprayed coatings, forming a protective apatite (Ca2RE8(SiO4)6O2) interlayer that effectively hindered CMAS infiltration at evaluated temperatures. The relatively higher Y:Yb atomic ratio (> 3) in the apatite grains indicate differential reactivity with molten CMAS and provides crucial insights into the CMAS corrosion mechanism. These findings highlight the potential of γ-Y1.5Yb0.5Si2O7 as a CMC coating material, emphasizing the need for tailored microstructural optimization as a thermal sprayed coating to enhance long-term performance in extreme gas turbine environments.

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High-temperature oxidation performance of novel environmental barrier coating 50HfO2-50SiO2/YxYb(2−x)Si2O7 at 1475 °C

Cited by 16 publications

References 51 publications

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

Environmental Barrier Coatings (EBCs) for Ceramic Matrix Composites

Thermal properties and calcium-magnesium-alumino-silicate (CMAS) interaction of novel γ-phase ytterbium-doped yttrium disilicate (γ-Y1.5Yb0.5Si2O7) environmental barrier coating material

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