Resistance of pure and mixed rare earth silicates against calcium‐magnesium‐aluminosilicate (CMAS): A comparative study

Wolf, M.; Mack, Daniel Emil; Guillon, Olivier; Vaßen, Robert

doi:10.1111/jace.17328

Cited by 42 publications

(24 citation statements)

References 58 publications

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“…Component analysis confirms the presence of CMAS. Sleeper, 36 14 a mixture of Yb monosilicate and disilicate was studied for resistance to CMAS. Their results showed that the thickness of the needle-shaped apatite was thin, but the fringe was thicker where the silicate mixture was uniformly mixed.…”

Section: Characterizationmentioning

confidence: 99%

“…The main corrosion factor is Ca, and it is thought that the Ca content of CMAS is higher than that of volcanic ash, and more of the Ca 2 Gd 8 (SiO 4 ) 6 O 2 (apatite) phase is formed by reacting with Gd 2 SiO 5 . Wolf et al 14 Yb 3+ (0.985 Å), which has a larger ionic radius than Sc 3+ (0.870 Å), provides a more reactive driving force for Ca. As compared with Gd 3+ (1.05 Å), the theory that the thickness of the reaction layer (apatite) becomes thicker as the size of ions increases is supported.…”

Section: Characterizationmentioning

confidence: 99%

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Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

et al. 2021

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Environmental barrier coatings (EBCs) protect silicon-based ceramic matrix composites (CMCs) from high temperatures. [1][2][3][4] CMCs have high-temperature performance and low density, which can greatly improve fuel consumption. CMCs' low density can reduce weight by up to 30% as compared to Ni-based superalloys. In addition, the insulation properties of EBCs are important, as the temperature of the hardware inside the engine changes at high temperatures. [5][6][7][8][9][10] In addition, demand is increasing for the thermal protection of CMCs in higher temperature applications. Research and development are being conducted to investigate the effect of actual volcanic ash during high-temperature operation. A composition similar to volcanic ash is being studied regarding the high-temperature interaction between artificial calciummagnesium-aluminosilicate (CMAS). [11][12][13][14][15][16][17] Recently, volcanoes have erupted in Japan, Australia, and Europe. Eruptions blow ash into the air, preventing flights from international airports and causing great economic damage. By minimizing EBC reactivity to volcanic ash, economic deterioration, and damage are effectively reduced. The problem is exacerbated by aircraft engines when the aircraft is flying in a desert or environment containing volcanic ash. Molten CMAS interacts thermochemically with EBCs to create new phases and adversely affects EBC performance. The accumulation of volcanic ash that reacts chemically to components can cause corrosion of the EBCs, degrading performance and reducing high-temperature capabilities. [18][19][20][21] In addition, corrosion resistance to the dissolved salt deteriorates, resulting in EBC and engine-component failure. Therefore, rare earth (RE)-doped silicates, which have very good oxidation resistance and can withstand high temperatures, are attracting attention for this kind of application. [22][23][24][25][26]

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Section: Characterizationmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

et al. 2021

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“…23,[31][32][33][34][35][36][37][38] T in these cases to determine the resin flow ing times corresponding to different infilt Preceramic polycarbosilane polymers as precursors to make ceramic fibers 10,3 trix. [7][8][9]40,41 The chemical and volume ch pany ceramization of the polymer during documented in several studies. For exam 42 ].…”

Section: Introductionmentioning

confidence: 99%

“…35,36 Conflicting observations on the stability of Yb 2 Si 2 O 7 materials in contact with CMAS have been reported, as some works observed the formation of the crystalline apatite phase Ca 2 Yb 8 (SiO 4 ) 6 O 2 while others did not. [36][37][38][39][40][41] However, the interaction of Yb 2 Si 2 O 7 with Na 2 SO 4 deposits, another known source of depositinduced degradation in turbine engines, has received very little attention in literature.…”

Section: Introductionmentioning

confidence: 99%

High‐temperature Na₂SO₄ interaction with air plasma sprayed Yb₂Si₂O₇ + Si EBC system: Topcoat behavior

Herweyer

Opila

2021

J Am Ceram Soc.

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The high-temperature interaction between ~2.5 mg/cm 2 of Na 2 SO 4 and an atmospheric plasma sprayed (APS) Yb 2 Si 2 O 7 topcoat-Si bond coat system on SiC CMC substrates was studied for times up to 240 h at 1000°C-1316°C in a 0.1% SO 2 -O 2 gaseous environment. Yb 2 Si 2 O 7 reacted with Na 2 SO 4 to form Yb 2 SiO 5 and an intergranular amorphous Na-silicate phase. Below 1200°C, the reaction was sluggish, needing days to cause morphological changes to the "splat microstructure" associated with APS coatings. The reaction was rapid at 1200°C and above, needing only a few hours for the entire topcoat to transform into a granulated microstructure consisting of Yb 2 SiO 5 and Yb 2 Si 2 O 7 phases. Na 2 SO 4 deposits infiltrated the Yb 2 Si 2 O 7 topcoat and transformed into an amorphous Na-silicate in less than 1 h at all exposure temperatures. Quantitative assessment of the Yb 2 SiO 5 area fraction in the topcoat showed a linear decrease over time at 1316°C, attributed to reaction with the SiO 2 thermally grown oxide (TGO) formed on the Si bond coat and rapid transport through the interpenetrating amorphous Na-silicate grain boundary phase. It was predicted that nearly 2 weeks is needed for complete removal of Yb 2 SiO 5 from the topcoat at 1316°C for a single applied loading of Na 2 SO 4 .

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“…Therefore, it is essential to investigate the hot corrosion behavior between the EBCs and NaVO 3 . Up to now, many studies have been conducted on thermal shock performance [12], calcia-magnesiaaluminosilicate (CMAS) corrosion [13,14] and wateroxygen corrosion [15,16] for Yb 2 Si 2 O 7 . Recently, Fan et al [17] investigated the hot corrosion behavior of γ-Y 2 Si 2 O 7 in the molten salt of Na 2 SO 4 and V 2 O 5 .…”

Section: Introductionmentioning

confidence: 99%

Hot corrosion behavior of Yb2Si2O7 ceramic by NaVO3 at 500 °C to 900 °C

Zhang

Zou

et al. 2021

Journal of Asian Ceramic Societies

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The hot corrosion behavior of Yb 2 Si 2 O 7 bulk exposed to NaVO 3 was investigated at 500-900°C. Results indicated that the hot corrosion reaction could occur at 500°C, the corrosion products were composed of YbVO 4 and SiO 2 at 500-900°C. The content of YbVO 4 and SiO 2 in the corrosion product at 500°C was small and the crystal size of YbVO 4 was fine. As temperature increased, a continuous and dense corrosion layer could be formed on the bulk surface, which prevented the hot corrosion reaction from occurring dramatically. The hot corrosion reaction products mainly consisted of rod-shaped YbVO 4 beyond 600°C. Since the corrosion reaction driving force increased with temperature, the rod-like YbVO 4 crystals tended to go from slender to plump; moreover, both ends changed from irregular lamination to regular quadrangular pyramid shape; also SiO 2 crystals partly changed from flocculent to ellipsoid shape. The hot corrosion mechanisms of Yb 2 Si 2 O 7 bulk exposed to NaVO 3 at 500-900°C were investigated based on the corrosion products.

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Resistance of pure and mixed rare earth silicates against calcium‐magnesium‐aluminosilicate (CMAS): A comparative study

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 42 publications

References 58 publications

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

High‐temperature Na₂SO₄ interaction with air plasma sprayed Yb₂Si₂O₇ + Si EBC system: Topcoat behavior

Hot corrosion behavior of Yb2Si2O7 ceramic by NaVO3 at 500 °C to 900 °C

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Resistance of pure and mixed rare earth silicates against calcium‐magnesium‐aluminosilicate (CMAS): A comparative study

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 42 publications

References 58 publications

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd2SiO5 for environmental barrier coatings

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd2SiO5 for environmental barrier coatings

High‐temperature Na2SO4 interaction with air plasma sprayed Yb2Si2O7 + Si EBC system: Topcoat behavior

Hot corrosion behavior of Yb2Si2O7 ceramic by NaVO3 at 500 °C to 900 °C

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Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd₂SiO₅ for environmental barrier coatings

High‐temperature Na₂SO₄ interaction with air plasma sprayed Yb₂Si₂O₇ + Si EBC system: Topcoat behavior