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Y2O3 stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) are prone to hot corrosion by molten salts. In this study, the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance. By optimizing the laser parameters, a ~18 μm smooth glazed layer with some vertical cracks was produced on the coating surfaces. The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000 ℃ for 4 h in V2O5 molten salt, and the results revealed that the modified one had improved corrosion resistance. After hot corrosion, the glazed layer kept structural integrity, with little evidence of dissolution. However, the vertical cracks in the glazed layer acted as the paths for molten salt penetration, accelerating the corrosion of the non-modified coating. Further optimization of the glazed layer is needed in the future work.


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Microstructure modification of Y2O3 stabilized ZrO2 thermal barrier coatings by laser glazing and the effects on the hot corrosion resistance

Show Author's information Lei GUOa,b( )Hui XINaZhao ZHANGcXinmu ZHANGaFuxing YEa,b
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
Tianjin Key Laboratory of Advanced Joining Technology, Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin 300072, China
School of Materials Science and Engineering, Liaocheng University, Liaocheng 252059, China

Abstract

Y2O3 stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) are prone to hot corrosion by molten salts. In this study, the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance. By optimizing the laser parameters, a ~18 μm smooth glazed layer with some vertical cracks was produced on the coating surfaces. The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000 ℃ for 4 h in V2O5 molten salt, and the results revealed that the modified one had improved corrosion resistance. After hot corrosion, the glazed layer kept structural integrity, with little evidence of dissolution. However, the vertical cracks in the glazed layer acted as the paths for molten salt penetration, accelerating the corrosion of the non-modified coating. Further optimization of the glazed layer is needed in the future work.

Keywords:

thermal barrier coatings (TBCs), air plasma spraying (APS), Y2O3 stabilized ZrO2, microstructure modification, laser glazing, V2O5 corrosion
Received: 13 August 2019 Revised: 03 January 2020 Accepted: 14 January 2020 Published: 11 March 2020 Issue date: April 2020
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Publication history

Received: 13 August 2019
Revised: 03 January 2020
Accepted: 14 January 2020
Published: 11 March 2020
Issue date: April 2020

Copyright

© The author(s) 2020

Acknowledgements

This research is sponsored by the National Natural Science Foundation of China (Grant No. 51971156).

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