| In this paper, the electrodeposition technology of the Ni-P and Ni-Cu-P alloy coatings on the aluminum and silicon alloy substrate were studied. By means of XRD. SEM, DSC, IM6 electrochemistry workstation etc.. The morphology, structure, content and performances of the Ni-P and Ni-Cu-P alloy coating were analyzed. The deposition mechanism of electroless nickel on aluminum and silicon alloy was discussed tentatively and argued on copper by the action and influence of the coating performance. The main content of the experiments and the results included:(1) By one dip nickel pretreatment, a compact and evengranular Ni-P and Ni-Cu-P alloy coating were deposited on the aluminum and silicon alloy substrate. By changing the content and condition of electroless bath, the technology and coating performance were studied. The optimal electroplating conditions and the influence of technology parameters were acquired.(2) The analysis results of XRD indicated that the Ni-P and Ni-Cu-P alloy coatings were amorphous structure. The surface shape indicated that the copper could diminish the crystal. The DSC results made know that the crystal temperature of the Ni-P alloy coating was lower than the Ni-Cu-P alloy coating's.(3) The results showed that the erode voltage of the Ni-P alloy coatings was lower than the Ni-Cu-P alloy coatings' by IM6 electrochemistry station in acid and alkali and salt solutions. At the same time, anodic polarization curves of Ni-Cu-P alloy coatings shifted to the positive direction relative to the Ni-P alloy coatings' in acid and alkali and salt solutions.(4) By the MVK-H3 hardness instrument, the hardness of the two coatings increased, and then decreased with the heat treatment temperatures. And the maximal hardness of Ni-Cu-P the alloy coating was the same to the Ni-P alloy coating's.(5) The testing results indicated that the hole rate of the Ni-P alloy coating was lower than the Ni-P alloy coating by hongdian means. |
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