Study on Densification and Corrosion Resistance of Conversion Coatings on Magnesium Alloy Wheel Hubs Surface
In order to improve the corrosion resistance of magnesium alloy wheel hub, a low - cost, environmentally friendly and corrosion - resistant conversion coating was prepared on the surface of magnesium alloy wheel hub. The effects of subsequent densification temperature and time on the morphology and...
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Department of Materials Protection
2021-03-01
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| Series: | Cailiao Baohu |
| Subjects: | |
| Online Access: | http://www.mat-pro.com/fileup/1001-1560/PDF/20210320.pdf |
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| Summary: | In order to improve the corrosion resistance of magnesium alloy wheel hub, a low - cost, environmentally friendly and corrosion - resistant conversion coating was prepared on the surface of magnesium alloy wheel hub. The effects of subsequent densification temperature and time on the morphology and electrochemical properties of cerium conversion film on Mg - 5.2Al - 0.5Mn - 1.8Ca alloy were investigated by SEM, EDS and electrochemical workstation. Results showed that the corrosion potential of the conversion film after phosphate densification treatment moved forward, the corrosion current density decreased and the polarization resistance increased, therefore, the corrosion resistance of the conversion film was enhanced. The corrosion resistance of the conversion film was the best when the densification temperature was 85 ℃. With the extension of the densification time, the corrosion potential of the conversion film first moved forward and then moved negatively, the corrosion current density first increased and then decreased, and polarization resistance first increased and then decreased. When the densification time was 60 s, the corrosion potential of the conversion film was the most positive, the corrosion current density was the smallest, and the polarization resistance was the largest, which showed the best corrosion resistance. The corrosion resistance of the original conversion film before densification treatment was mainly related to the surface cracks and the structure of the conversion film, the corrosion resistance of the conversion film after densification treatment was mainly related to the newly formed dense CePO4 film. When the densification temperature was 85 ℃ and the densification time was 60 s, the conversion film had the best corrosion resistance. |
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| ISSN: | 1001-1560 |