| Ni-Cu alloy coating and Ni-Cu/Ti O2 composite coating were prepared on Q235 steel by pulse electrodeposition.The effects of p H,bath temperature,average current density on Ni-Cu alloy coatings and the effects of Ti O2 content,p H,average current density,stirring rate on Ni-Cu/Ti O2 composite coating were investigated by single factor experiment.The results showed that the optimum technological parameters for preparing Ni-Cu alloy coating were:p H value was 5.0,bath temperature was 30℃,average current density was 8 A·dm-2;The optimal addition amount of Ti O2 particles for the preparation of Ni-Cu/Ti O2 composite coating was determined as 0.2g·L-1,and the optimal process parameters were:p H value was 5.0,average current density was 8 A·dm-2,and stirring rate was 40 r/min.Electrochemical methods such as CV,EIS and timing current were used to analyze the electrodeposition behavior of Ni-Cu/Ti O2 composite coating and Ni-Co-Cu alloy coating at different p H values.The electrodeposition process of Ni-Cu/Ti O2 composite coating was an irreversible process mainly controlled by electrochemistry,and the nucleation mechanism was continuous nucleation.Electrodeposition of Ni-Co-Cu alloy coatings at different p H values was an irreversible process from diffusion control to electrochemical control,and the nucleation mechanism is instantaneous nucleation.Ni-Cu/Ni-Cu（Ti O2）multilayer films and Ni-Cu/Ni-Co-Cu multilayer films were prepared on Q235 steel by double-groove pulse electrodeposition.The cross section morphology,composition and corrosion resistance of the multilayer films were characterized by SEM,EDS,Tafel curve and electrochemical impedance spectroscopy.The results showed that the Ni-Cu/Ni-Cu（Ti O2）multilayer films of corrosion resistance was better than Ni-Cu/Ti O2 composite coating and Ni-Cu alloy coating;Ni-Cu/Ni-Co-Cu multilayer films of corrosion resistance was better than Ni-Co-Cu alloy coating and Ni-Cu alloy coatingFigure 63;Table 33;Reference 83... |
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