Title: A new method to prepare MgO and base for further electroless nickel deposition on magnesium substrate

Authors: Jothi Sudagar; Jianshe Lian; Guangli Bi; Jiang Jing; Jiaan Liu

Addresses: College of Materials Science and Engineering, Nanling Campus, Jilin University, Changchun – 130022, China ' College of Materials Science and Engineering, Nanling Campus, Jilin University, Changchun – 130022, China ' College of Materials Science and Engineering, Nanling Campus, Jilin University, Changchun – 130022, China ' College of Materials Science and Engineering, Nanling Campus, Jilin University, Changchun – 130022, China ' College of Materials Science and Engineering, Nanling Campus, Jilin University, Changchun – 130022, China

Abstract: The present research uses the safer hydrogen halide to prepare the MgO-MgI₂/MgBr₂ layers onto AZ91 magnesium alloy in alkaline solution. The water-soluble metal salts (MgI₂/MgBr₂) were not responsible for the corrosion protection; whereas Mg(OH)₂ formed first and then converted to MgO by heat-treatments and this MgO was responsible for the corrosion protection. The electrochemical results showed that the development of MgO mitigated the corrosion process and improved the corrosion resistance. This new treatment was then used as a pre-treatment for further electroless nickel (EN) deposition and it showed the good corrosion current density and better corrosion potential on the magnesium substrate. This new treatment and EN depositions were characterised by XPS and SEM. The electrochemical polarisation and EIS test of these EN depositions were evaluated in 3.5 wt.% NaCl. In addition, pitting behaviour of these EN depositions were evaluated by linear sweep voltammetry test.

Keywords: magnesium oxide; MgO; electroless nickel deposition; magnesium substrates; corrosion resistance; pitting corrosion; magnesium alloys; hydrogen halide; electrochemical testing; linear sweep voltammeter; LSV; scanning electron microscope; SEM; X-ray photoemission spectroscopy; XPS.

DOI: 10.1504/IJSURFSE.2013.053696

International Journal of Surface Science and Engineering, 2013 Vol.7 No.2, pp.97 - 108

Received: 13 Sep 2011
Accepted: 30 Apr 2012
Published online: 02 Jul 2014 *

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