Effect of irregular microcracks on the hot corrosion behavior and thermal shock resistance of YSZ thermal barrier coatings

Yan, Kai; Xiang, Yanhong; Yu, Haiyuan; Li, Zhenrui; Wu, Yajing; Sun, Jian

doi:10.1016/j.surfcoat.2021.128038

Cited by 22 publications

(3 citation statements)

References 55 publications

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“…When turbine engines consume low-quality fuels containing impurities such as vanadium, sulfur, and sodium or are operated for marine applications, hot corrosion from the corrosive salts can be a crucial factor to the durability of TBCs. These corrosive salts will melt and penetrate the coating at high temperatures and react with the basic rare earth oxides, resulting in the decomposition of the coatings [10,11]. The hot corrosion behavior of YSZ coating in vanadate-sulfate slats has been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts

Yan,

Xiang,

Lei

et al. 2024

J. Phys.: Conf. Ser.

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In this study, the LaYbZr2O7 (LYZ) thermal barrier coatings (TBCs) were deposited by air plasma spray (APS) and were subjected to hot corrosion in the single V2O5 salts and the mixture of V2O5+Na2SO4 with different Na2SO4 content at 1000 °C. The reaction mechanism and corrosion layer evolution of the LYZ coating in different corrosive molten were comparatively investigated. After hot corrosion in the single V2O5 salt, the surface of the LYZ coating develops a dense corrosion layer, which could keep structural integrity with the extension of exposure time, indicating the LYZ coating showed higher resistance to the V2O5 corrosion. However, the dense layer failed to form on the surface of the LYZ coating in the V2O5+Na2SO4 mixed salts. With the increase of Na2SO4 content, the corrosion products formed on the surface of the LYZ coating gradually decreased, and the corrosion layer disappeared. The dominant reason for the difference was that the addition of Na2SO4 resulted in the acidity reduction of the mixed salts, which eventually caused a decrease in the corrosion rate. Compared with the single V2O5, the V2O5+Na2SO4 mixed salts showed higher penetration ability in the LYZ coating and could be more damaging.

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Section: Introductionmentioning

confidence: 99%

Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts

Yan,

Xiang,

Lei

et al. 2024

J. Phys.: Conf. Ser.

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“…These fuel contaminants could create a corrosive environment of sulfate and vanadate (YVO 4 and Na 2 O) on the surface of the TBCs during prolonged operation. 5,6 Due to the instability of the t ′ -phase, these compounds can penetrate the top coat defects in the molten state and react with Y 2 O 3 , speeding the tetragonal-to-monoclinic transformation process. 7 The phase transition may produce volume expansion and stress, resulting in TBC degradation or premature failure.…”

Section: Introductionmentioning

confidence: 99%

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Avcı,

Karabaş,

Akdoğan Eker

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The purpose of this research is to look into the effect of laser surface modification on the hot corrosion and hot corrosion + calcium–magnesium aluminosilicate (CMAS) resistance of YSZ thermal barrier coating. Metco AMDRY 997 (Ni–22Cr–10Al–Y) powder was coated as a bond coat on the AISI 304L stainless steel substrate using a high-velocity oxy-fuel spray technique. As a ceramic top layer, 204 NS YSZ (ZrO2·8Y2O3) particles were plasma sprayed on the bond coat. Following that, the entire coating surface was treated with a 20-kHz pulsed CO2 laser to increase the coatings’ surface performance. A corrosion test was carried out in a box furnace for 20 h at 1050 °C. SEM images of laser-glazed coatings revealed denser surfaces than those of air-spraying coatings. The laser-modified coating is more resistant to hot corrosion than unmodified coatings. The X-ray diffraction analysis revealed that the reaction between yttria (Y2O3) and V2O5 resulted in the formation of YVO4 crystals as a corrosion product. According to energy dispersive spectroscopy results, laser-glazed coatings reduced molten salt diffusion from surface to bond coat. As a result, laser-glazed coatings demonstrated improved hot corrosion resistance and decreased corrosion products on the bond coat zone. After the hot corrosion test, the laser-treated composite had a 55% lower thermally grown oxide layer than untreated APS YSZ. The optimum laser parameter was used as 77.7 W laser power, 120 mm/s scanning speed, and 215 mm laser distance.

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“…Using the finite element method, Zhi-Y et al explained the YSZ coating peel fractures as the connection between the interface peak and the cracks within the YSZ [25]. Kai et al came to the conclusion that the connection of the fractures within the YSZ would result in a rupture region later in the coating's lifetime, thereby accelerating the coating's peeling [26]. Consequently, the crack extension and connection problem will be a significant factor in coating failure; however, previous studies on thermal barrier coatings focused on the analysis of internal stress and interface morphology of the coating, concentrating on the TBC failure mode and the corresponding failure mechanism, while simplifying or ignoring the effect of the morphology of the porous YSZ on crack extension.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hot Spot within Combustion Liner on YSZ Crack Propagation Mode

Guo

Wang²,

Shi³

et al. 2023

Coatings

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On the aero-engine combustor liner, a phenomenon of overheating resembling a hot spot exists, accompanied by a preferential peeling of the YSZ thermal barrier coating that will negatively affect the service life of the component. The hot spot temperatures will affect the ineffectiveness of YSZ, so in this paper, the morphological and property changes of YSZ sintering is investigated experimentally, and a coupled analysis of the YSZ crack propagation mode under the hot spot is performed using ABAQUS. The results show that the pore fractal size D of YSZ increases by 15%. Inside the hot spot region, the coating has a shear stress of 75 MPa. By inserting cohesive units globally in the FEM to simulate the random crack initiation and propagation, unlike the thinning of YSZ layered peeling caused by uniform superheating, the hot spot will cause the crack initiation at the tip of the pores inside the coating and the oblique propagation, eventually forming an oblique crack connection through the pores. When the temperature gradient reaches 30 K/mm, the crack propagation is 40% greater than in a uniform temperature field; consequently, the YSZ in the hot spot boundary region with a greater temperature gradient results in more severe bulk peeling.

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Effect of irregular microcracks on the hot corrosion behavior and thermal shock resistance of YSZ thermal barrier coatings

Cited by 22 publications

References 55 publications

Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts

Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Effect of Hot Spot within Combustion Liner on YSZ Crack Propagation Mode

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Effect of irregular microcracks on the hot corrosion behavior and thermal shock resistance of YSZ thermal barrier coatings

Cited by 22 publications

References 55 publications

Hot corrosion behaviours of the LaYbZr2O7 thermal barrier coatings in different corrosive salts

Hot corrosion behaviours of the LaYbZr2O7 thermal barrier coatings in different corrosive salts

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Effect of Hot Spot within Combustion Liner on YSZ Crack Propagation Mode

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Product

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Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts

Hot corrosion behaviours of the LaYbZr₂O₇ thermal barrier coatings in different corrosive salts