| WANG Xin-yue,WANG Ji-hui,GAO Zhi-ming,XIA Da-hai,HU Wen-bin.Effect of Heat Treatment on Microstructure and Corrosion Resistance of Electrodeposited Nanocrystalline Chromium Coating[J],48(12):59-67 |
| Effect of Heat Treatment on Microstructure and Corrosion Resistance of Electrodeposited Nanocrystalline Chromium Coating |
| Received:August 13, 2019 Revised:December 20, 2019 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2019.12.007 |
| KeyWord:Cr coating electrodeposition heat treatment microstructure corrosion resistance |
| Author | Institution |
| WANG Xin-yue |
Tianjin Key Laboratory of Composite & Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| WANG Ji-hui |
Tianjin Key Laboratory of Composite & Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| GAO Zhi-ming |
Tianjin Key Laboratory of Composite & Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| XIA Da-hai |
Tianjin Key Laboratory of Composite & Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin , China |
| HU Wen-bin |
Tianjin Key Laboratory of Composite & Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin , China |
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| Abstract: |
| The work aims to improve the microstructure and corrosion resistance of nanocrystalline chromium coating on H13 steel. Nanocrystalline chromium coating was prepared on H13 steel by electrodeposition technique. Heat treatment was applied to control the microstructure and corrosion resistance of coating. The surface morphology, roughness, phase structure, microhardness and corrosion resistance of the chromium coating were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffractometer (XRD), Vickers microhardness tester and neutral salt spray test (NSS), respectively. Nanocrystalline chromium coating with body-centered cubic structure was successfully prepared on the surface of H13 steel by electrodeposition technique. The size of grains and microcracks increased with the increase of heat treatment temperature (200~600 ℃) and duration (1~2 h). When the heat treatment temperature reached 400 ℃, Cr2O3 oxide layer was detected on the surface of Cr coating, and the degree of oxidation increased with the increase of the heat treatment temperature and duration. In addition, the hardness of Cr coating decreased with the increase of heat treatment temperature and duration. After the heat treatment at 600 ℃ for 2 h, the microhardness of the coating was about (499.8±9.3)HV0.2, which decreased by 33% compared with that of the as-plated coating ((749.0±13.2)HV0.2). However, the coatings with the best corrosion resistance were obtained after heat treatment at 500 ℃ and 600 ℃ and no obvious corrosion defects were found on the coating after salt spray test, and the protection rating was 10. With the increase of heat treatment temperature and duration, the grain size and the degree of the surface oxidation increase, thereby enhancing the corrosion resistance of the coating. |
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