摘要

An innovative composite plating apparatus for complex-shaped cylinders has been proposed. It allows the cylinders not to be immersed entirely in the electrolyte. Using circulating-solution co-deposition (CSD) technique in the novel plating apparatus, Ni-SiC composite coatings can be deposited on the inner surfaces of cylinders, while the outer remains intact. It is of great significance for the engine cylinders whose outer surfaces require high precision to meet the need of specific functions and cannot be corroded by the electrolyte during electrodeposition. The morphology, structure, hardness, corrosion and wear resistance of the Ni-SiC coating in comparison with that of Ni coating have been analyzed. Characterization experiments reveal that the volume fraction of the deposition rate is about 83 mu m/30 min. In comparison with pure Ni coating, Ni-SiC composite coating exhibits better anti-corrosion performance, higher hardness as well as greater wear resistance. The predominant wear mechanism for Ni-SiC is abrasive wear and oxidational wear. These results prove that the CSD technique is an efficient technology to prepare Ni-SiC composite coatings with excellent corrosion and wear resistance at a high deposition rate. The composite plating apparatus proposed for large-scale industrialization plan is worth to be highly recommended.