Corrosion resistance of AZ91D magnesium alloy with electroless plating pretreatment and Ni-TiO{sub 2} composite coating
- School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)
- School of Materials Science and Engineering, Southwest University, Chongqing, 400715 (China)
In this paper, a protective multilayer coating, with electroless Ni coating as bottom layer and electrodeposited Ni-TiO{sub 2} composite coating as top layer, was successfully prepared on AZ91D magnesium alloy by a combination of electroless and electrodeposition techniques. Scanning electron microscopy and X-ray diffraction were employed to investigate the surface, cross-section morphologies and phase structure of coatings, respectively. The electrochemical corrosion behaviors of coatings in 3.5 wt.% NaCl solutions were evaluated by electrochemical impedance spectroscopy, open circuit potential and potentiodynamic polarization techniques. The results showed that the corrosion process of Ni-TiO{sub 2} composite coating was mainly composed of three stages in the long-term immersion test in the aggressive media, and could afford better corrosion and mechanical protection for the AZ91D magnesium alloy compared with single electroless Ni coating. The micro-hardness of the Ni-TiO{sub 2} composite coating improved more than 5 times than that of the AZ91D magnesium alloy.
- OSTI ID:
- 22066185
- Journal Information:
- Materials Characterization, Vol. 61, Issue 3; Other Information: Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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