Thermal stability and sintering behavior of plasma sprayed nanostructured 7YSZ, 15YSZ and 5.5SYSZ coatings at elevated temperatures

Loghman-Estarki, Mohammad Reza; Razavi, Reza Shoja; Jamali, Hossein

doi:10.1016/j.ceramint.2016.05.203

Cited by 30 publications

(6 citation statements)

References 43 publications

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“…However, YSZ displays a crystalline-phase change at long lifetimes or at very high temperatures (>1200 °C) which causes a damage or failure of the TBC. This latter, along with the growing need in the last years for increasing the operational temperature of gas turbines has fuelled an intense research activity to develop coatings systems with enhanced thermal isolation and performance [7][8][9]. These advanced TBC coatings requirements have also led to the seek of new TBC materials, the development of new coating architecture for the existing materials or a combination of both approaches.…”

Section: Introductionmentioning

confidence: 99%

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Carnicer

Orts

Moreno

et al. 2018

Ceramics International

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In this research, Suspension Plasma Spraying (SPS) technique was used for the thermal deposition of a multicomponent mixture made up of an Y-TZP/Al2O3 matrix with SiC particles. Two suspensions of Y-TZP and Al2O3 with different SiC particle content (6 wt% and 12 wt%) were tested as feedstocks in the SPS process. Three stand-off distances were varied in order to assess coating microstructure and quantify SiC particles preservation in the final coatings. Coatings were characterised in terms of porosity, microstructure and phase distribution. The estimate of the amount of SiC particles present in the coating was carried out by XRD technique. Findings showed typical cauliflower-like SPS microstructure which intensifies with stand-off distance. Coatings porosity values varied significantly between 8 to 25% whereas minimum porosity was found for the intermedium stand-off distance of 40 mm. Microstructure analysis also revealed the presence of SiC particles in the coatings which was confirmed by EDX analysis, overall XRD test as well as TG analysis compared with SiC powder. Finally, quantification of SiC content in the final coatings by means of XRD analysis showed that most of SiC particles (c.a 80 %) of the feedstocks were preserved in the final coatings.

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Section: Introductionmentioning

confidence: 99%

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Carnicer

Orts

Moreno

et al. 2018

Ceramics International

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Section: Thermal Cycling Property and Microstructural Evolutionmentioning

confidence: 99%

“…Meanwhile, some coarse cracks are found in the lamellar interface of YSZ layer. The accumulated sintering stress is provided the driving force for the initiation and propagation of cracks [36,37]. For the YSZ/NiCoCrAlY gradient coatings, the temperature difference of the bottom region has a higher value, therefore, the thermal expansion mismatch stress at the bottom region is higher than that of the surface sintering stress at the upper region, which finally leads to the separation of coating and bonding layer.…”

Section: Thermal Cycling Property and Microstructural Evolutionmentioning

confidence: 99%

Bonding and Thermal-Mechanical Property of Gradient NiCoCrAlY/YSZ Thermal Barrier Coatings with Millimeter Level Thickness

et al. 2021

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The thermal insulation properties of thermal barrier coatings (TBCs) can be significantly improved with increasing the coating thickness. However, due to the weak bonding of high-thickness TBCs, the resulting low reliability and short lifetime greatly limits their application under some severe operating conditions. In this study, a novel and high-efficiency synchronous dual powder feeding method is used to deposit a series of gradient NiCoCrAlY/YSZ coatings with millimeter level thickness. The tensile bonding strengths and residual stress state of coatings are evaluated in order to explore the effect of thickness on the bonding strength of coating. The results suggested that, due to some micro-convex structure at the “GC/TC” interface and inside “GC” layer, the bonding strength of 1000-μm-thickness gradient NiCoCrAlY/YSZ TBCs with the 4:6 and 2:8 hybrid ratios is over 44 MPa compared to the common TBCs. The fracture position gradually shifts from NiCoCrAlY bond coat to NiCoCrAlY/YSZ transition zone and finally to the YSZ top coat owing to the different position of residual stress concentrations. After thermal cycling tests, the 1000-μm-thickness gradient coating exhibits a higher thermal cycling life. Some coarse cracks initiate and propagate at the bottom region of TBCs, which is mainly due to thermal expansion mismatch stress that finally results in the failure of the gradient coating between the “BC” layer and the substrate.

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“…TBCs of the conventional turbine blades typically include MCrAlY bond coat (in which M could be Ni, Co or a combination of both) and a top coat composing Yttria stabilized Zirconia (YSZ: ZrO 2 -8 wt.%Y 2 O 3 ) deposited by plasma spray-based methods such as atmospheric plasma spray (APS) [1,7,8]. However, the application of YSZ has been limited due to its low sintering resistance [9][10][11][12] and susceptibility to oxygen diffusion; especially in the cases of exposure to certain corrosive species [7,13,14].…”

Section: Introductionmentioning

confidence: 99%

ZrO₂ 9.5Y₂O₃ 5.6Yb₂O₃ 5.2Gd₂O₃; a promising TBC material with high resistance to hot corrosion

Bahamirian

Hadavi

Farvizi

et al. 2020

Journal of Asian Ceramic Societies

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Hot corrosion in Na 2 SO 4-V 2 O 5 environments has been regarded as a major challenge in the destruction of thermal barrier coatings (TBCs). The present study introduces a new TBC (ZrO 2 9.5Y 2 O 3 5.6Yb 2 O 3 5.2Gd 2 O 3 (ZGYbY)) with enhanced resistance to hot corrosion compared to the yttria-stabilized zirconia (YSZ). ZGYbY and YSZ were applied on CoNiCrAlY, as a bond coat to nickel-based superalloy (IN738LC) using the atmospheric plasma spray (APS) technique. Hot corrosion behavior of TBCs was investigated in a cyclic approach (4 hours for each cycle) using Na 2 SO 4-55 wt.% V 2 O 5 salts at 950°C. The findings showed the higher hot corrosion resistance of ZGYbY TBC compared to YSZ coating system. Regarding the lower basicity of Yb 2 O 3 and Gd 2 O 3 (compared to Y 2 O 3), the driving force for the reaction of Yb 2 O 3 /Gd 2 O 3 + Na 2 SO 4-55 wt.% V 2 O 5 will be lower than that of Y 2 O 3 + Na 2 SO 4-55 wt.% V 2 O 5. Moreover, the stabilizers in the zirconia coating could be dissolved by sodium sulfate and vanadium oxide at high temperatures giving rise to the dis-integrity of the TBCs.

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Thermal stability and sintering behavior of plasma sprayed nanostructured 7YSZ, 15YSZ and 5.5SYSZ coatings at elevated temperatures

Cited by 30 publications

References 43 publications

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Bonding and Thermal-Mechanical Property of Gradient NiCoCrAlY/YSZ Thermal Barrier Coatings with Millimeter Level Thickness

ZrO₂ 9.5Y₂O₃ 5.6Yb₂O₃ 5.2Gd₂O₃; a promising TBC material with high resistance to hot corrosion

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Thermal stability and sintering behavior of plasma sprayed nanostructured 7YSZ, 15YSZ and 5.5SYSZ coatings at elevated temperatures

Cited by 30 publications

References 43 publications

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

Bonding and Thermal-Mechanical Property of Gradient NiCoCrAlY/YSZ Thermal Barrier Coatings with Millimeter Level Thickness

ZrO2 9.5Y2O3 5.6Yb2O3 5.2Gd2O3; a promising TBC material with high resistance to hot corrosion

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Product

Resources

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ZrO₂ 9.5Y₂O₃ 5.6Yb₂O₃ 5.2Gd₂O₃; a promising TBC material with high resistance to hot corrosion