Zn Coatings on AZ91D Magnesium Alloy Prepared by Electroplating From the Electrolyte Containing SnO_2 sol

摘要

A new method has been devised to obtain a Zn coating on the AZ91D magnesium alloy from the base electrolyte of ZnSO_4 and K_4P_2O_7 by electroplating. To improve the properties of the coating, a SnO_2 sol was prepared and added in the electrolyte. The effects of the SnO_2 sol addition on the morphologies, compositions and phase structures of the plated coatings were investigated by scanning electron microscopy (SEM), energy dispersion spectrometry (EDS) and X-ray diffraction (XRD). The results reveal that the addition of SnO_2 in the solution changes the polarization behavior of the electrolyte and the compositions of the plated coating. The plated coating formed in the electrolyte with an addition of SnO_2 sol are more uniform and provide a better protection for the AZ91D substrate.