Matrix Development for Water Vapor Resistant SiC-Based Ceramic Matrix Composites

Golden, Robert A.

doi:10.18130/v3b34z

Cited by 2 publications

(4 citation statements)

References 61 publications

(138 reference statements)

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“…EBC diffusivity and resulting silicon bond coat oxidation were represented by the bulk EBC oxygen diffusion coefficients at 1400 • C in addition to a conditional statement based on the maximum diffusion coefficient standard already described. 36 Values of −log 10 (D bulk ) were used as the input into the FoM so that all data can be compared without spanning multiple orders of magnitude. The thermal stresses represent thermomechanical behavior of EBCs and include the CTE, CTE anisotropy of the EBC, and the CTE of the steam reaction product.…”

Section: Ebc Figure Of Meritmentioning

confidence: 99%

“… j The oxygen diffusion coefficient of Ba 0.75 Sr 0.25 Al 2 Si 2 O 8 (BSAS) is unknown. The oxygen diffusion coefficient for Al 6 Si 2 O 13 (mullite) at 1400°C was extrapolated from 1119−1319°C data 36 to be used as an estimate for BSAS.…”

Section: Ebc Figure Of Meritmentioning

confidence: 99%

“…A conditional statement was used to favor EBCs that produce a protective reaction layer to prevent further CMAS ingress. EBC diffusivity and resulting silicon bond coat oxidation were represented by the bulk EBC oxygen diffusion coefficients at 1400°C in addition to a conditional statement based on the maximum diffusion coefficient standard already described 36 . Values of −log 10 ( D bulk ) were used as the input into the FoM so that all data can be compared without spanning multiple orders of magnitude.…”

Section: Ebc Figure Of Meritmentioning

confidence: 99%

“…Of utmost importance, amorphous silica can devitrify forming cristobalite during service, where a β‐ to α‐cristobalite phase transformation occurs around 270°C with an associated 6% volume reduction, further damaging the EBC‐bond coat interface 35 . EBC candidates should have low oxygen and water vapor diffusivity, where an industry limit has been placed at a maximum oxygen diffusion coefficient of 1 × 10 −11 cm 2 /s, 36 assuming the oxidant can also quickly reach the bond coat through microstructural defects, such as porosity or cracks, resulting from either the APS process, the thermal stress release upon engine cycling, or from the porosity created with the EBC‐steam reaction process.…”

Section: Introductionmentioning

confidence: 99%

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Holistic comparison of environmental barrier coating material candidates through design of a figure of merit

Ridley,

Pinnisi,

Opila

2024

J Am Ceram Soc.

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The first figure of merit for environmental barrier coating (EBC) materials was designed through a ranking system for material properties pertaining to established EBC failure modes in service. Seven past, present, and novel EBC candidate materials were used in the figure of merit design: SiO2, Ba0.75Sr0.25Al2Si2O8 (BSAS), HfSiO4, Yb2Si2O7, Yb2SiO5, Yb2O3, and YbPO4. Utilizing compiled data from the literature, the presented figure of merit verified Yb2Si2O7 as the state‐of‐the‐art candidate with optimal EBC properties and inferred that YbPO4 should be considered as a potentially viable EBC material candidate. The figure of merit allows for a holistic comparison of EBC candidates and informs experimental and computational search efforts for next‐generation complex EBCs. Clear knowledge gaps found through this work include CaO–MgO–Al2O3–SiO2 (CMAS)‐resistant coatings, EBC lifetimes before delamination, and oxidant diffusion rates in relevant EBC microstructures. It was shown that while some materials show promise for solving a single key failure mode for EBCs (i.e., CMAS reactivity), a community‐wide goal should be placed on materials development to achieve acceptable resistance against all major failure modes, which are interconnected. Novel compositionally complex EBC materials, in addition to layered EBC architectures, show promise for the optimization of material properties for long‐lifetime EBCs in combustion environments.

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Section: Ebc Figure Of Meritmentioning

confidence: 99%