The Feasibility Study On The Ni60/WC-10Co4Cr Coating Prepared By HVOF As Replacement For The Electroplating Hard Chromium Coating

The application of Electroplated Hard Chromium（EHC）Coating is restricted increasingly due to its pollution of the environment and the lack of service capability.Currently,the WC-10Co4Cr coating prepared by High-Velocity Oxygen-Fuel（HVOF）spraying technology has considerable effect in replacing the EHC coating,but the high cost of raw materials and subsequent processing limit its wide application.For this purpose,this paper mixed Ni60 powder and WC-10Co4Cr powder by mechanical mixing with different proportion as the spraying powder,and prepared five Ni60/WC-1OCo4Cr coatings in 16Mn substrate using HVOF spraying process.With a view to providing solution for a wider range of alternative EHC coating,the property of wear,corrosion and impact of the Ni60/WC-1OCo4Cr coating were studied in depth and compared with the EHC coating.Drew the following conclusion:In terms of wear performance,the Ni60/60%WC-1OCo4Cr coating prepared by HVOF spraying process showed the closest to EHC coating,and its performance in sliding wear has reached the level for the replacement of the latter.For the corrosion performance,the lower the WC-10Co4Cr content,the better the corrosion resistance of the Ni60/WC-lOCo4Cr coating.Compared with the EHC coating,the Ni60/60%WC-lOCo4Cr coating with compact structure and moderate performance is expected to show better corrosion resistance in the actual service environment.All of the coating did not peel off the substrate after 1,100,1000 and 5000 shocks.The numerical simulation results showed that the initial failure position of the coating is located at the edge of the impact crater on the coating surface.Except for WC-10Co4Cr coating,no macroscopic flake peeling occurred on the surface of all Ni60/WC-1OCo4Cr coating.And their impact pit size is obviously lower than the EHC coating.The anti-impact performance of the Ni60/60%WC-1OCo4Cr coating was significantly better than that of the EHC coating.According to the current market situation and experimental results,the price of Ni60 powder is only 1/3 of that of WC₁0Co4Cr powder,and the deposition efficiency of Ni60/WC-1OCo4Cr powder is about 10%higher than that of WC-1OCo4Cr powder.In addition,the Ni60/WC-1OCo-4Cr coating prepared by HVOF is relatively easy to grind and polish,and the corresponding post-processing cost is also significantly lower than that of WC-10Co4Cr coating.Therefore,Ni60/60%WC-1OCo4Cr coating prepared by HVOF not only meets the requirement of replacing EHC coating in performance,but also has a lower raw material and post-processing cost than traditional WC-1OCo4Cr coating,which is more feasible to replace EHC coating.