| GUO Lei,XIN Hui,ZHANG Xin-mu,YE Fu-xing,GAO Yuan.Effects of Laser Surface Modification on Phase Stability and Microstructures of Thermal Barrier Coatings in V2O5 Molten Salt[J],49(1):41-48 |
| Effects of Laser Surface Modification on Phase Stability and Microstructures of Thermal Barrier Coatings in V2O5 Molten Salt |
| Received:August 20, 2019 Revised:January 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.01.005 |
| KeyWord:thermal barrier coatings (TBCs) air plasma spray (APS) Y2O3 stabilized ZrO2 laser modification V2O5 corrosion |
| Author | Institution |
| GUO Lei |
1.School of Materials Science and Engineering, Tianjin University, Tianjin , China; 2.Tianjin Key Laboratory of Advanced Joining Technology, Tianjin , China; 3.Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin , China |
| XIN Hui |
1.School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| ZHANG Xin-mu |
1.School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| YE Fu-xing |
1.School of Materials Science and Engineering, Tianjin University, Tianjin , China; 2.Tianjin Key Laboratory of Advanced Joining Technology, Tianjin , China; 3.Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin , China |
| GAO Yuan |
1.School of Materials Science and Engineering, Tianjin University, Tianjin , China |
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| Abstract: |
| This work aims to improve the corrosion resistance of Y2O3 partially stabilized ZrO2 (YSZ) thermal barrier coatings to molten salt. In this study, A pulsed Nd:YAG laser system was applied to modify surfaces of air plasma spray (APS) YSZ coatings, and the laser parameters were optimized. The as-sprayed and laser-modified coatings were both exposed to hot corrosion tests at 700 ℃ and 1000 ℃ for 4 h in V2O5 molten salt. The phase constitution、microstructure and chemical composition of as-sprayed and laser-modified coatings before and after hot corrosion tests were characterized by XRD、SEM and EDS, and the effects of laser modification on phase stability of coatings were analyzed by calculating the content of m-ZrO2 on the surfaces of coatings after hot corrosion. Laser glazing layers on coating surfaces presented a dense columnar crystal structure, with some vertical cracks through the layer. Like the as-sprayed coating, the modified layer remained metastable tetragonal (t’) phase. Corrosion products of modified coatings corroded at 700 ℃ and 1000 ℃ for 4 h were ZrV2O7, YVO4 and small amounts of monoclinic (m) ZrO2, and m-ZrO2 and YVO4, respectively. Under the same molten salt corrosion conditions, the type of corrosion products of non-modified YSZ coating was the same as that of the modified coating, but with a higher m-ZrO2 content, which indicated that more decomposition of t’ phase due to corrosion. Therefore, laser modification can improve the t’ phase stability of YSZ coating, and the modified coatings have a better corrosion resistance to molten salt. However, molten salt penetration into the coating through the vertical crack in the glazing layer is undesirable, which is harmful to the long-term stability of the coatings. |
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