Anodizing of AZ91D magnesium alloy using environmental friendly alkaline borate-biphthalate electrolyte
(1. Department of Chemistry, Zhejiang University, Hangzhou 310027, China;
2. Department of Chemistry, Tianshui Normal University, Tianshui 741000, China;
3. Magnesium Technology Co., Ltd., Chinese Academy of Sciences, Jiaxing 314051, China)
2. Department of Chemistry, Tianshui Normal University, Tianshui 741000, China;
3. Magnesium Technology Co., Ltd., Chinese Academy of Sciences, Jiaxing 314051, China)
Abstract: A kind of environmental friendly anodizing routine for AZ91D magnesium alloy, based on an alkaline borate-potassium acid phthalate (KAP) electrolyte, was studied. The effect of KAP on the properties of the anodized film was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. The results showed that the anodizing process, surface morphology, thickness, phase structure and corrosion resistance of the anodized film were strongly dependent on the concentration of KAP. In the presence of adequate KAP, a compact and smooth anodized film with excellent corrosion resistance was obtained.
Key words: anodizing; magnesium alloy; potassium acid phthalate; environmental friendly electrolyte; corrosion performance