Combined effect of internal and external factors on sintering kinetics of plasma-sprayed thermal barrier coatings

Guang-rong, LI; Wang, Li-Shuang; Yang, Guan-Jun

doi:10.1016/j.jeurceramsoc.2018.12.053

Cited by 38 publications

(11 citation statements)

References 44 publications

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“…There are various other studies which have shown the effect of sintering on reduction in porosity content and volume shrinkage. [30][31][32][33][34] Ilavsky's small angle scattering study suggests that certain types of pores and interfaces can undergo localized sintering even at 800°C to 900°C consistent with the knowledge of diffusion kinetics in YSZ. However, the implications of these low-temperature (<1000°C) microstructure changes on the elastic properties have not be studied, especially given that the coating has 8-9 times lower bending modulus than their completely dense counterparts largely due to the high porosity content and imperfect bonding between splats.…”

Section: Introductionsupporting

confidence: 65%

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Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂

Lal¹,

Kumar²,

Sampath

et al. 2019

J Am Ceram Soc

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Evolution in bending modulus and accompanying microstructure of free‐standing air plasma‐sprayed Y2O3‐stabilized ZrO2 subjected to thermal exposure, from 800°C to 1300°C, has been studied. The bending modulus was measured using custom‐made miniaturized cantilevers, which was loaded using a nanoindenter. Variation in the bending modulus was compared with the density change. The coating shows two domains of behavior of modulus variation with density: the low temperature/time domain wherein the bending modulus doubles without measurable change in the density and the high‐temperature domain where modulus increases monotonically with density. Finite element (FE) analysis was carried out using cross‐sectional micrographs of coatings to measure the elastic modulus of the actual coating and compared with experimentally observed values. The modulus values predicted by FE analysis are 70%‐80% higher than the experimentally observed values. An analytical model has been proposed to corelate the microcracks density and elastic modulus, which is in reasonable agreement with the experimentally measured values.

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Section: Introductionsupporting

confidence: 65%

“…They found the surface area of cracks and voids kept decreasing beyond 600°C and almost 33% of surface area of voids and microcracks have been lost from as sprayed coating to 1000°C heat‐treated coating. There are various other studies which have shown the effect of sintering on reduction in porosity content and volume shrinkage …”

Section: Introductionmentioning

confidence: 99%

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂

Lal¹,

Kumar²,

Sampath

et al. 2019

J Am Ceram Soc

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“…Therefore, the difference between the durability of the two types of TBCs depended on other factors in the absence of TGO thickness. It has been well documented that the sintering [11][12][13][14][15][58][59][60][61], gradient thermal cycling temperature [16][17][18][19], and roughness of bond coat/topcoat interface [7,[20][21][22][23] also affect the durability of samples. In this case, these other factors were all identical in these two types of TBCs, except for the microstructures of the bond coats.…”

Section: Thermal Cyclic Lifetime Of Tbcsmentioning

confidence: 99%

“…The spallation of the ceramic topcoat, typically made of yttria-stabilized zirconia (YSZ), is one of the factors that hinders the service of TBCs. The failure of atmospheric plasma-sprayed (APS) TBCs can be affected by many factors, such as TGO growth [1,2,[4][5][6][7][8], thermal expansion mismatch [1,[8][9][10], YSZ sintering [11][12][13][14][15], the temperature gradient across YSZ coating [16][17][18][19] and the profile of the bond coat surface [7,[20][21][22][23], etc. Thermal expansion mismatch between the YSZ coating and the substrate is one of the most critical factors that presently affects the durability of TBCs [9,10,19,24,25].…”

Section: Introductionmentioning

confidence: 99%

The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Peng

Dong

et al. 2019

Coatings

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The durability of atmospheric plasma-sprayed thermal barrier coatings (APS TBCs) with a double-layer bond coat was evaluated via isothermal cycling tests under 1120 °C. The bond coat consisted of a porosity layer deposited on the substrate and an oxidation layer deposited on the porosity layer. Two types of double-layer bond coats with different thickness ratios of the porosity layer to the oxidation layer (type A: 1:2 and type B: 2:1, respectively) were prepared. The results show that the porosity layer was oxidation free, the oxidation layer included a fraction of well-distributed α-Al2O3. The coefficient of thermal expansion of the oxidation layer was about 11.2 × 10−6 K−1, which was rather lower than that of the porosity layer. Thus, the oxidation layer can be regards as a secondary bond coat between ceramic topcoat and traditional bond coat. The thermal cyclic lifetime of type A TBCs was about 60 cycles, which exceeded 1.2 times the durability of type B TBCs. The delamination cracks in both TBCs all propagated in the ceramic topcoat, which were all identical to those in traditional TBCs. Therefore, the design of the double-layer bond coat affected the stress level rather than the stress distribution in TBCs.

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“…This also implies that a typical way to obtain the smaller grain structure is to reduce the thickness of single layer. The interfaces are very dense, without presence of micro/nano-scale porosities or other phases [73][74][75][76][77].…”

Section: Interface Problemmentioning

confidence: 99%

Key Problems Affecting the Anti-Erosion Coating Performance of Aero-Engine Compressor: A Review

Sun

Jiao

et al. 2019

Coatings

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Sand erosion has always been a key threat to the performance and service life of aero-engines. The compressor, the key component installed at the front of the aero-engine, suffers the most from sand erosion, especially compressors serving in deserts. Ceramic hard coating is a traditional way to improve the hardness and wear resistance of cutting and grinding tools. It may also be used to improve the erosion resistance of aero- engine compressor. However, the mechanism of erosion damage is complicated, which may include wear, secondary erosion, anisotropic erosion, impact, and fatigue. Recent research discovered the major problems with ceramic hard coating on aero-engine compressors. In this paper, these following problems are discussed: the design of coating material and structure, the preparation method and technology, the effects of droplets and clusters of coating surface, microstructure and characteristics of interface. The review of the major problems and possible solutions discussed in this paper may contribute to the future research on erosion coating theoretically and practically.

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Combined effect of internal and external factors on sintering kinetics of plasma-sprayed thermal barrier coatings

Cited by 38 publications

References 44 publications

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂

The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Key Problems Affecting the Anti-Erosion Coating Performance of Aero-Engine Compressor: A Review

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Combined effect of internal and external factors on sintering kinetics of plasma-sprayed thermal barrier coatings

Cited by 38 publications

References 44 publications

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y2O3‐stabilized ZrO2

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y2O3‐stabilized ZrO2

The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Key Problems Affecting the Anti-Erosion Coating Performance of Aero-Engine Compressor: A Review

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Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂

Low‐temperature stiffening of air plasma‐sprayed 7 wt% Y₂O₃‐stabilized ZrO₂