Study On Chemical Plating Ni-P/PTFE Composite Coating And Its Frictional Properties

With the continuous development of industrial production,a single electroless Ni-P alloy coating can not meet the needs of the industry.Therefore,researchers began to study the electroless composite coating.Adding nm PTFE particles into the Ni-P coating can not only enhance the wear resistance of the composite coating,but also enhance the corrosion resistance of the coating.In this study,the process parameters of electroless plating ni-p-ptfe and the performance of electroless plating ni-p-ptfe were studied and evaluated based on the evaluation indexes of hardness,deposition rate,corrosion resistance and frictional property of composite plating.Secondly,in order to improve the hardness of the coating and obtain better friction performance,nm PTFE was compounded with nano-hard particles?Ti O₂,Si O₂,Si C,Al₂O₃?,and the influence of surfactant?FC4?and buffer?Na Ac?was considered.Therefore,the experiment was arranged by five-factor four-level orthogonal table.Comparison of ni-p/PTFE composite coating ni-p/PTFE?Si O₂,Si C,Al₂O₃,Ti O₂?composite coating performance,the results are as follows:1.After experimental study,the optimal formula of electroless Ni-P-PTFE plating is:25g/L Ni SO₄,30g/L Na H₂PO₂,2mg/L thiourea?TU?,20g/L citric acid+15g/L succinic acid,20g/L Na Ac,18mg/L FC4,2mg/L PTFE,temperature 85±1?,p H 5.0,loading ratio 1dm²/L,plating time 1h,Ni-P ratio 0.37,deposition rate 10.7?m/h,hardness 195HV,friction coefficient 0.36,corrosion resistance time 31.8h.2.Through orthogonal test,it is concluded that the composite coating of nano Ni-P-PTFE/Si C is A₄B₃C₂D₄?25g/L buffer,14mg/L FC4,0.4g/L Si C,2.5g/L PTFE?is close,fine and flat in the composite with nano Si C.From the analysis of friction coefficient,the average friction coefficient of the four orthogonal tests,the average friction coefficient of the optimal solutions of Ti O₂,Si O₂,Si C and Al₂O₃are 0.320,0.329,0.326 and 0.328,respectively.The average friction coefficients of the four optimal solutions are not much different.3.According to the performance comparison of composite coating,the hardness and friction coefficient of single PTFE composite coating are 165 HV and 0.265respectively,and the hardness and friction coefficient of ni-p/PTFE?Al₂O₃,Si O₂,Si C,Ti O₂?composite coating are as follows:178.3 HV,189.2 HV,180.5 HV,178.3 HV?0.328,0.329,0.326,0.321;When the heat treatment temperature is 300?,the hardness and tribology of the composite coating are the best.The hardness and friction coefficient of electroless plating Ni-P-PTFE,Ni-P-PTFE/Si O₂and Ni-P-PTFE/Si C are respectively:190HV and 0.403,228.1HV and 0.502,207HV and 0.412.By comparing the polarization curves,the corrosion resistance of Ni-P-PTFE is better.