Abstract： Ni(P) chemical plating and pure tin hot dipping were used to coat the surface of AZ91D magnesium alloy to prepare Ni(P)-Sn doublelayer coating film. After 2 hours of thermal diffusion treatment at 220℃, the structure and corrosion properties of the interface of clad layer were analyzed. Scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) were used for interface structure detection and elemental analysis. Xray diffraction (XRD)was used to investigate the surface phase structure of the Ni(P)-Sn coating film, and polarization curves were used to study the corrosion resistance of the coating film before and after thermal treatment. The results indicate that the Ni-P layer with continuous distribution along the interface can efficiently prevent the diffusion of Sn into Ni layer. The Ni3Sn4 phase floats in Sn layer with blockshape to destruct the single phase of coating film and cause the reduction of decay resistance after thermal treatment.
2014, Vol. 35 
