| ZHAN Zhongwei,ZHANG Qi,LIU Xiaohui,WANG Shuaixing,PANG Zhiwei,SUN Zhihua,GE Yulin,WANG Qichao,DU Nan.Effect of CeO2 Particles on Growth Behavior and Wear/Corrosion Resistance of Micro-arc Oxidation Coating on 7075 Aluminum Alloy[J],53(17):71-82 |
| Effect of CeO2 Particles on Growth Behavior and Wear/Corrosion Resistance of Micro-arc Oxidation Coating on 7075 Aluminum Alloy |
| Received:September 17, 2023 Revised:January 08, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.17.006 |
| KeyWord:7075-T6 aluminum alloy micro-arc oxidation CeO2 particles microhardness wear resistance corrosion resistance |
| Author | Institution |
| ZHAN Zhongwei |
Aviation Key Laboratory of Science and Technology on advanced Corrosion and Protection for Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing , China |
| ZHANG Qi |
Aviation Key Laboratory of Science and Technology on advanced Corrosion and Protection for Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing , China |
| LIU Xiaohui |
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang , China |
| WANG Shuaixing |
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang , China |
| PANG Zhiwei |
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang , China;AECC Xi'an Power Control Technology Corporation, Xi'an , China |
| SUN Zhihua |
Aviation Key Laboratory of Science and Technology on advanced Corrosion and Protection for Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing , China |
| GE Yulin |
Aviation Key Laboratory of Science and Technology on advanced Corrosion and Protection for Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing , China |
| WANG Qichao |
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang , China |
| DU Nan |
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang , China |
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| Abstract: |
| In order to further improve the wear resistance and corrosion resistance of micro-arc oxidation (MAO) coatings on the 7075-T6 aluminum alloy, CeO2 particles are added to silicate and phosphate a mixed electrolyte system for composite oxidation. The influence of CeO2 particle content on the growth process of MAO coatings is explored from the change laws in oxidation voltage, discharge behavior and film thickness. The surface microstructure, cross-sectional microstructure, and element distribution of MAO coatings prepared in electrolytes with different content of CeO2 particles are analyzed by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The corrosion resistance and wear resistance of different coatings are analyzed through potentiodynamic polarization curves, electrochemical impedance spectroscopy, simulated immersion corrosion tests, and ball disc wear tests. The corrosion and wear mechanisms of MAO/CeO2 composite coatings are also analyzed. The results show that the composite of CeO2 particles changes the energy consumption distribution of the coating-forming process of MAO coatings for 7075 aluminum alloy, accelerates the discharge breakdown and increases the termination voltage of the oxidation process. The total energy consumption of preparing MAO/CeO2 composite coatings is about 60-120 kJ higher than that of preparing ordinary coatings. The addition of CeO2 particles reduces the growth rate of MAO coatings, but is helpful to improve the compactness and bonding strength of MAO coatings. The density of MAO/CeO2 composite coatings is about 5%-20% higher than that of ordinary MAO coatings of equivalent thickness. The critical load when the composite film ruptures is also increased by 1-3 N compared with ordinary oxide coatings. Besides, the microhardness of MAO coatings increases with the increase of the CeO2 particle content in the electrolyte. The CeO2 particles mainly enter into the MAO coatings by melting or embedding. CeO2 particles are mainly melt in the coating in a molten state when the composite amount is low; both molten and particulate CeO2 can be observed within the coatings if the composite amount is high. The composite of CeO2 particles also enhances the wear resistance and corrosion resistance of MAO coatings. Compared with ordinary MAO coatings, the friction coefficient of MAO/CeO2 composite coatings is also generally decreased by about 0.2, only slight abrasive wear is present on the surface after friction, and the specific wear rate is also lower, resulting in better wear resistance. Besides, the self-corrosion current density of MAO/CeO2 composite coatings is also decreased by at least 50%, the corrosion weight gain is smaller and the corrosion is milder after soaking in simulated seawater for 2 000 h. When 10 g/L CeO2 particles are added to the electrolyte, the comprehensive performance of composite oxide coatings is the best, and its corrosion current density and specific wear rate is only 1/10 of those of ordinary oxide coatings. In summary, CeO2 particles in the electrolyte can be melted or embedded into MAO coatings of aluminum alloy, effectively reducing the micropores and defects in MAO coatings, improving the density and microhardness of coatings, and improving the corrosion resistance and wear resistance of MAO coatings. |
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