Cracking Behavior of Gd2Zr2O7/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray

Mohamed Amer; Nicholas Curry; Qamar Hayat; Rohit Sharma; Vit Janik; Xiang Zhang; Jon Nottingham; Mingwen Bai

doi:10.3390/coatings13010107

Cracking Behavior of Gd₂Zr₂O₇/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray

Mohamed Amer, Nicholas Curry, Qamar Hayat, Rohit Sharma, Vit Janik, Xiang Zhang, Jon Nottingham, Mingwen Bai

Research output: Contribution to journal › Article › peer-review

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Abstract

A new multi-layered thermal barrier coating system (TBCs) containing gadolinium zirconate (GZ, Gd₂Zr₂O₇) and yttria-stabilized zirconia (YSZ) was developed using suspension plasma spray (SPS) to improve the overall thermal cycling performance. This study focuses on the cracking behavior of the GZ/YSZ TBC after thermal exposure to find out the key factors that limit its lifetime. Different cracking behaviors were detected depending on the thermal treatment condition (i.e., horizontal cracks within the ceramic layer and at the thermally grown oxide (TGO)/YSZ interface) which can be related to stresses developed through thermal expansion mismatch and increased TGO thickness beyond a critical value, respectively. A reduction in hardness of bond coat (BC) was measured by nanoindentation and linked with the thermally activated grain growth mechanism. The hardness and elastic modulus of ceramic layers (GZ and YSZ) showed an increased trend after treatment that contributed to the interfacial cracks.

Original language	English
Article number	107
Number of pages	19
Journal	Coatings
Volume	13
Issue number	1
DOIs	https://doi.org/10.3390/coatings13010107
Publication status	Published - 6 Jan 2023

Bibliographical note

Copyright: © 2023 by the authors.Licensee MDPI, Basel, Switzerland.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Keywords

gadolinium zirconate (GZ)
thermal barrier coatings (TBCs)
multi-layered structure
suspension plasma spray (SPS)
microstructure
hardness
elastic modulus

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10.3390/coatings13010107Licence: CC BY

PublishedFinal published version, 2.96 MBLicence: CC BY

Cite this

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title = "Cracking Behavior of Gd2Zr2O7/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray",

abstract = "A new multi-layered thermal barrier coating system (TBCs) containing gadolinium zirconate (GZ, Gd2Zr2O7) and yttria-stabilized zirconia (YSZ) was developed using suspension plasma spray (SPS) to improve the overall thermal cycling performance. This study focuses on the cracking behavior of the GZ/YSZ TBC after thermal exposure to find out the key factors that limit its lifetime. Different cracking behaviors were detected depending on the thermal treatment condition (i.e., horizontal cracks within the ceramic layer and at the thermally grown oxide (TGO)/YSZ interface) which can be related to stresses developed through thermal expansion mismatch and increased TGO thickness beyond a critical value, respectively. A reduction in hardness of bond coat (BC) was measured by nanoindentation and linked with the thermally activated grain growth mechanism. The hardness and elastic modulus of ceramic layers (GZ and YSZ) showed an increased trend after treatment that contributed to the interfacial cracks.",

keywords = "gadolinium zirconate (GZ), thermal barrier coatings (TBCs), multi-layered structure, suspension plasma spray (SPS), microstructure, hardness, elastic modulus",

author = "Mohamed Amer and Nicholas Curry and Qamar Hayat and Rohit Sharma and Vit Janik and Xiang Zhang and Jon Nottingham and Mingwen Bai",

note = "Copyright: {\textcopyright} 2023 by the authors.Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).",

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T1 - Cracking Behavior of Gd2Zr2O7/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray

AU - Amer, Mohamed

AU - Curry, Nicholas

AU - Hayat, Qamar

AU - Sharma, Rohit

AU - Janik, Vit

AU - Zhang, Xiang

AU - Nottingham, Jon

AU - Bai, Mingwen

N1 - Copyright: © 2023 by the authors.Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

PY - 2023/1/6

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N2 - A new multi-layered thermal barrier coating system (TBCs) containing gadolinium zirconate (GZ, Gd2Zr2O7) and yttria-stabilized zirconia (YSZ) was developed using suspension plasma spray (SPS) to improve the overall thermal cycling performance. This study focuses on the cracking behavior of the GZ/YSZ TBC after thermal exposure to find out the key factors that limit its lifetime. Different cracking behaviors were detected depending on the thermal treatment condition (i.e., horizontal cracks within the ceramic layer and at the thermally grown oxide (TGO)/YSZ interface) which can be related to stresses developed through thermal expansion mismatch and increased TGO thickness beyond a critical value, respectively. A reduction in hardness of bond coat (BC) was measured by nanoindentation and linked with the thermally activated grain growth mechanism. The hardness and elastic modulus of ceramic layers (GZ and YSZ) showed an increased trend after treatment that contributed to the interfacial cracks.

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