Preparation and Corrosion Behavior of Ti - Zr Conversion Coating on the Surface of Aluminum Alloy
In order to further improve the corrosion resistance of aluminum alloy, Ti - Zr conversion coatings were prepared on LY12 aluminum alloy, using H2TiF6 and H2ZrF6 as main film - forming agents and sodium hexametaphosphate as auxiliary film - forming agent. The effects of convers...
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| Main Author: | |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Department of Materials Protection
2021-04-01
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| Series: | Cailiao Baohu |
| Subjects: | |
| Online Access: | http://www.mat-pro.com/fileup/1001-1560/PDF/20210419.pdf |
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| Summary: | In order to further improve the corrosion resistance of aluminum alloy, Ti - Zr conversion coatings were prepared on LY12 aluminum alloy, using H2TiF6 and H2ZrF6 as main film - forming agents and sodium hexametaphosphate as auxiliary film - forming agent. The effects of conversion solution’s pH value and conversion time on the corrosion resistance of conversion coating were systematically studied. And the relationship among the surface morphology, composition and corrosion resistance of conversion coating was established by SEM, EDX, electrochemical test and total immersion test. Results showed that when the temperature of the conversion solution was 40℃, the optimal pH value of the conversion solution was 4.5 and the optimal conversion time was 15 min. The conversion coating mainly contained Ti, Al, O elements and a small amount of Zr element. It could be inferred that the main components of the conversion coating were TiO2, ZrO2 and Al2O3. The continuous dense oxide film could obviously resist the corrosion of Cl-, and thus improved the corrosion resistance significantly. |
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| ISSN: | 1001-1560 |