Transition from penetration cracking to spallation in environmental barrier coatings on ceramic composites

Summers, William D.; Begley, Matthew R.; Zok, Frank W.

doi:10.1016/j.surfcoat.2019.125083

Cited by 19 publications

(12 citation statements)

References 22 publications

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“…Additionally, they are thermochemically incompatible with the thermally grown silica (TGS) scale. A common design concept that mitigates these challenges involves bi‐layer EBCs, with a disilicate in contact with the TGS and a thin outer layer of monosilicate …”

Section: Discussionmentioning

confidence: 99%

“…A common design concept that mitigates these challenges involves bi-layer EBCs, with a disilicate in contact with the TGS and a thin outer layer of monosilicate. 32,33 5 | CONCLUSIONS YMS cannot coexist in equilibrium with a wide spectrum of silicate deposits of interest in gas turbine applications. In principle, reactions should proceed until the deposits are completely consumed.…”

Section: Implications For Ebc Development and Performancementioning

confidence: 99%

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Reactions of molten silicate deposits with yttrium monosilicate

et al. 2020

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The article addresses effects of silicate deposit composition on reactions with yttrium monosilicate (YMS), a candidate environmental barrier coating for aero-engine components. Computed phase equilibria are used to predict the nature and relative proportions of reaction products and the extent of YMS consumption upon reaction with twelve deposits of varying composition at 1300°C. These predictions are compared with results of a corresponding experimental study on three exemplary deposits.Although the nature and sequence of reaction products formed (typically apatite and yttrium disilicate) depend on the Ca:Si ratio of the deposit, the degree of consumption of YMS at equilibrium is relatively insensitive to deposit composition and is predicted to proceed to a greater extent than that in yttrium disilicate. However, sluggish reaction kinetics associated with the formation of a thin apatite layer above the YMS prevents reactions from reaching their terminal equilibrium states within the experimental times investigated (250 hours). For deposit loadings of 18 mg/cm 2 (corresponding to a thickness of about 100 µm), the degree of consumption following 250 hours exposures is only about 10%-40% of the predicted terminal values, depending on deposit composition. K E Y W O R D Schemical reactions, CMAS, Environmental barrier coating, yttrium silicate 2920 | SUMMERS Et al.

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Section: Discussionmentioning

confidence: 99%

Section: Implications For Ebc Development and Performancementioning

confidence: 99%

Reactions of molten silicate deposits with yttrium monosilicate

et al. 2020

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“…This is due to the crack healing phenomena-e.g., by means of chemical reactions with atmospheric oxygen at high temperatures-which results in filling the cracks and prolonging the coating durability [60][61][62]. In contrast, the spallation can potentially remove the entire coating resulting in rapid degradation of the underlying substrate [63,64]. Therefore, the ML3 coating can be the most promising for such applications because it is characterized by the enhanced spallation resistance compared with the other coatings, which can be attributed to the largest relative thickness of the metal layers in this coating.…”

Section: Uniaxial Tensionmentioning

confidence: 99%

The Effect of Multilayer Architecture and Ta Alloying on the Mechanical Performance of Ti-Al-N Coatings under Scratching and Uniaxial Tension

Шугуров

Kuzminov

2021

Metals

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The present work is focused on a comparative study of the effect of Ti-Al interlayers and Ta alloying on the mechanical behavior of Ti1−xAlxN coatings under normal contact pressure and in-plane straining. The contact loading of the samples was carried out by scratch testing, while the in-plane tensile straining was performed by uniaxial tension of the coated steel substrates. The Ti0.45Al0.55N and Ti0.43Al0.45Ta0.12N monolithic coatings as well as the Ti0.45Al0.55N/Ti0.45Al0.55 multilayer coatings with different number and thickness of the layers were deposited by DC magnetron sputtering. It was found that the introduction of the ductile Ti0.45Al0.55 layers into the Ti0.45Al0.55N coating and alloying with Ta led to their significant toughening. The improved toughness of the Ti0.43Al0.45Ta0.12N coating coupled with high residual compressive stress and high hardness resulted in its strongest resistance to cracking under scratching and tensile straining among the coatings studied. The multilayer coating with the thickest metal layers exhibited the improved resistance to delamination under in-plane straining.

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“…22 Additionally, the material should be mechanical, thermal, optical, and chemically stable at operating temperature. 23,24 For example, at high operating temperature, the absorber materials can get oxidized that will change their optical, thermal, and mechanical properties. [24][25][26] Conventionally, a mixture of metal particles and dielectric matrix, known as cermet, is coated, or deposited on a metallic substrate (IR reflector) to prepare a multilayered selective solar absorber (SSA).…”

Section: Introductionmentioning

confidence: 99%

“…23,24 For example, at high operating temperature, the absorber materials can get oxidized that will change their optical, thermal, and mechanical properties. [24][25][26] Conventionally, a mixture of metal particles and dielectric matrix, known as cermet, is coated, or deposited on a metallic substrate (IR reflector) to prepare a multilayered selective solar absorber (SSA). 27 Generally, the top layer of an absorber coating is a dielectric material and the bottom layer is a reflective mirror.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond laser‐produced optical absorbers for solar‐thermal energy harvesting

Singh

Chen

2021

EcoMat

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Optical absorbers are a key component in all solar‐thermal energy technologies. Cermet‐based solar absorbers are commonly used in solar‐thermal applications. However, due to their multilayered structures, these absorbers have limited thermal conductivity and mechanical stability at the interfaces. Femtosecond laser processing is a single‐step, environmentally friendly, and monolithic approach that can directly transform a metal surface to a solar absorber through surface patterning without adding additional weight, hazard, or complexity. In this review, we will focus on femtosecond‐laser induced broadband and selective solar absorbers and their utilizations in solar thermoelectric generators and solar‐thermal water purification. We will discuss the laser surface patterning and the procedure to control the size, distribution, and composition of the surface structures that are responsible for optical absorbance/emittance. Several multifunctional solar absorber surfaces produced by femtosecond‐laser processing and their possible energy applications are also discussed.

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Transition from penetration cracking to spallation in environmental barrier coatings on ceramic composites

Cited by 19 publications

References 22 publications

Reactions of molten silicate deposits with yttrium monosilicate

Reactions of molten silicate deposits with yttrium monosilicate

The Effect of Multilayer Architecture and Ta Alloying on the Mechanical Performance of Ti-Al-N Coatings under Scratching and Uniaxial Tension

Femtosecond laser‐produced optical absorbers for solar‐thermal energy harvesting

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