Improvement of Adhesion Strength of Electroless Nickel Coating on AZ91D by Anodized Oxide Interlayer
(0) Nickel-oxide duplex coatings were successfully deposited on magnesium alloy (AZ91D) by anodizing and electroless nickel-phosphorus plating processes.The anodizing interlayer was used to increase the adhesion strength of Ni-P layer.The electroless Ni-P coating enhances the corrosion resistance of the anodic oxide layer.Specimen of AZ91D magnesium alloy was polished firstly.The anodizing process was preceded in alkaline anodizing solution at 24℃,and the bath voltage maintained at 70 volts for 2 hours.Successive electroless Ni-P plating was used to achieve the sandwich structure.The surface morphologies of the coatings were observed by field-emission scanning electron microscopy (FE-SEM).The adhesion strength was measured by pull-offtester.The electrochemical behavior of coatings with corrosion resistance in 3.5 wt.% NaC1 solution was evaluated by potential polarization curve.The experimental results showed that the adhesion strength of directly deposited coating and duplex coating were 115.4 kgf/cm2 and 142.2 kgf/cm2,respectively.The adhesion strength of coatings on AZ91D magnesium alloy was improved by the synergistic effect between anodized magnesium oxide and Ni-P layer in duplex coating.
Adhesion Anodizing Corrosion resistance Electroless plating Magnesium alloys
Hsien-Ta Hsu Tsong-Jen Yang
Department of Materials Science and Engineering,Feng Chia University,Taichung,Taiwan
国际会议
The 6th Cross-Strait Conference on Advanced Engineering Materials (第六届海峡两岸工程材料研讨会)
南京
英文
90-95
2011-11-08（万方平台首次上网日期，不代表论文的发表时间）