| MA Wenqiang,ZHAO Xiaoqin,AN Yulong,BU Zhenyu,SUN Chufeng,ZHOU Huidi,CHEN Jianmin.Effect of Y2O3 Content on Microstructure and Mechanical Properties of Al2O3-Y2O3 Composite Coatings Deposited by Atmospheric Plasma Spraying[J],53(7):208-216 |
| Effect of Y2O3 Content on Microstructure and Mechanical Properties of Al2O3-Y2O3 Composite Coatings Deposited by Atmospheric Plasma Spraying |
| Received:August 15, 2023 Revised:September 26, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.07.022 |
| KeyWord:atmospheric plasma spraying Al2O3-Y2O3 composite coating porosity microstructure mechanical properties |
| Author | Institution |
| MA Wenqiang |
School of Chemical Engineering, Northwest Minzu University, Lanzhou , China;State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| ZHAO Xiaoqin |
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| AN Yulong |
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| BU Zhenyu |
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| SUN Chufeng |
School of Chemical Engineering, Northwest Minzu University, Lanzhou , China |
| ZHOU Huidi |
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
| CHEN Jianmin |
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou , China |
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| Abstract: |
| The work aims to investigate the effect of doping with different mass fractions of Y2O3 on the microstructure and mechanical properties of Al2O3-Y2O3 composite coatings. To achieve this objective, Al2O3 coatings and Al2O3-Y2O3 composite coatings with Y2O3 contents of 10wt.%, 20wt.%, 30wt.%, and 40wt.% were produced on the surface of Q235 mild steel by atmospheric plasma spraying technique. The morphology, microstructure and elemental distribution of the powders and the different coatings were analyzed by SEM and EDS. The phase composition of the powders and coatings was analyzed by XRD. The mechanical properties of the coatings, such as microhardness, modulus of elasticity, and fracture toughness, were tested and analyzed with a microhardness tester, a nanoindentation tester and an electronic universal testing machine. The results showed that the phase composition of Al2O3 powder were α-Al2O3, and the Al2O3 phases in Al2O3 coating and its Al2O3-Y2O3 composite coating were composed of α-Al2O3 and γ-Al2O3. Besides, Y2O3 powder and coating were all composed of c-Y2O3, but the Y2O3 of Al2O3-Y2O3 composite coating was composed of c-Y2O3 and m-Y2O3. The addition of Y2O3 had a certain inhibitory effect on the generation of γ-Al2O3. With the increase of Y2O3 content, the insufficiently fused particles on the surface of the Al2O3-Y2O3 composite coating gradually increased, and the surface became rougher. The Al2O3 and Y2O3 phases in the composite coating showed a laminar distribution, and the combined interface of Al2O3 and Y2O3 was more dense, and the Y2O3 in the powder was well retained in the coating. The Al2O3-Y2O3 composite coating doped with 10wt.% Y2O3 had the lowest porosity and the densest coating. When the content of Y2O3 exceeded 10wt.%, the porosity increased with the increase of Y2O3 content. In terms of mechanical properties, the Al2O3 coating had the highest microhardness value (1 209HV0.3). The cross-sectional microhardness was less than the surface microhardness in all coatings. The microhardness of Al2O3-Y2O3 composite coatings gradually decreased with the increase of Y2O3 content. Among them, when the doping amount of Y2O3 in the Al2O3-Y2O3 composite coating was 10wt.%, the decrease in the microhardness value compared to the Al2O3 coating was not obvious. In the Weibull distribution image, the slope of the straight line after linear fitting of the Al2O3-10wt.% Y2O3 composite coating was the largest, indicating that the coating was the densest. The results of the nanoindentation experiments showed that the Al2O3 coating had the highest nanoindentation hardness (14.95 GPa) and elastic modulus (227 GPa). The larger the content of Y2O3 in the composite coating, the smaller the values of nanoindentation hardness and elastic modulus. The Al2O3-10wt.% Y2O3 composite coating had the best elastic recovery of 48.3% and the best resistance to plastic deformation. The results of the three-point bending experiments showed that the Al2O3-10wt.%Y2O3 composite coating had the largest stress and strain values (σ=742.56 MPa, ε=3.08%) when fracture occurred, and its fracture toughness was the best. The results showed that the Al2O3-Y2O3 composite coating doped with 10wt.% Y2O3 had the densest microstructure and the best overall mechanical properties. |
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