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Effects of Cobalt(II)Sulfate Addition on Structure and Corrosio n Resistance of Alloy Micro-arc oxidation Coating on the ZL108 Aluminum

Jie Hu, School of New Energy and Materials, Southwest Petroleum University, Chengdu, 610500, China
2020 International Journal of Electrochemical Science  
Micro-arc oxidation (MAO) coatings were formed on ZL108 aluminum alloy in silicate electrolyte with CoSO 4 . Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical workstation were used to investigate the effects of CoSO 4 on the microstructure, phase composition, elemental distribution and corrosion resistance of the MAO coatings. The results showed that the addition of CoSO 4 increased the micro arc oxidation voltage, which
more » ... voltage, which increased the coating formation rate, resulting in an increase in the thickness of the MAO coatings. After the addition of CoSO 4 , the discharge on the coating surface was more uniform, which made the coating flatter. The phases of the MAO coatings were mainly composed of α-Al 2 O 3 , γ-Al 2 O 3 and SiO 2 . The XPS test results showed that CoSO 4 was converted to CoO and Co 3 O 4 , which made the MAO coatings denser. Electrochemical corrosion tests showed that the corrosion resistance of the coatings with CoSO 4 was improved. Therefore, the addition of CoSO 4 can optimize the structure of the MAO coating and improve its comprehensive properties.
doi:10.20964/2020.06.78 fatcat:mpjb7dlx6nallokvybsdkzovce