| ZHAO Jian,LIU Guang,MA Bing,ZHENG Zi-yun,LI Tian-yi,DAI Yu.Preparation of Ni/Cu-Cr3C2/Co Gradient Coating in the Combination of Laser Alloying and Laser Cladding Technologies on Copper Products[J],47(8):162-169 |
| Preparation of Ni/Cu-Cr3C2/Co Gradient Coating in the Combination of Laser Alloying and Laser Cladding Technologies on Copper Products |
| Received:April 24, 2018 Revised:August 20, 2018 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2018.08.023 |
| KeyWord:copper alloy laser surface alloying laser cladding gradient coating microhardness wear mechanism |
| Author | Institution |
| ZHAO Jian |
Ningbo Branch, China Academy of Ordnance Science, Ningbo , China |
| LIU Guang |
Ningbo Branch, China Academy of Ordnance Science, Ningbo , China |
| MA Bing |
Ningbo Branch, China Academy of Ordnance Science, Ningbo , China |
| ZHENG Zi-yun |
Ningbo Branch, China Academy of Ordnance Science, Ningbo , China |
| LI Tian-yi |
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo , China |
| DAI Yu |
Ningbo Branch, China Academy of Ordnance Science, Ningbo , China |
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| Abstract: |
| The work aims to improve surface hardness and wear resistance of copper alloys. A Ni/Cu-Cr3C2/Co gradient coating was prepared successfully on the surface of copper alloy by combining laser alloying and laser cladding technologies. Phase composition and microstructure of the gradient coating were analyzed by X-ray diffractometer, scanning electron micro scope, energy dispersive spectrometer, etc. Microhardness and wear resistance of the gradient coating were evaluated by hardness test and friction-wear test. The alloying transition layer was dense and had a single columnar crystal structure, and phases were mainly composed of α-(Cu,Ni), Ni3Al and NiAl. Undissolved Cr3C2 particles were distributed in the Cr3C2/Co composite cladding layers. A large number of rod-like (or needle-like) M23C6 and M7C3 carbides centered around the undissolved Cr3C2 particles, which could effectively improve hardness of the cladding layer. Microhardness of the gradient coating gradually increased from the 80HV (substrate) to 640HV (cladding layer), and friction-wear loss of the gradient coating was only 1/8 of copper substrate. There was much debris on the worn surface of copper substrate due to massive destruction, and its wear mechanism was mainly adhesive wear. Due to weak internal bonding force, a large number of fatigue wear surfaces appeared on the Cr3C2/Co sprayed coating, and the wear mechanism was surface fatigue wear. However, worn surface of the Ni/Cu-Cr3C2/Co gradient coating was relatively smooth, there were some slight "furrows", and its wear mechanism was typical abrasive wear. Because of the existence of Cr3C2, M23C6 and M7C3 phases, microhardness and wear resistance of the gradient coating are significantly improved. Meanwhile, composition and properties of the coating show a certain gradient change, which improves the compatibility between copper substrate and coating. |
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