A Chromium-free and Low Fluoride Pre-treatment Process of Electroless Nickel Plating on Magnesium Alloys

作者：Xie Zhihui^*

来源：Rare Metal Materials and Engineering, 2016, 45(1): 192-196.

• magnesium alloys
• electroless plating
• pickling-activation
• environmentally friendly
• corrosion

The effects of three different pretreatments on direct electroless nickel plating of magnesium alloys have been studied by several methods in order to obtain an environmentally friendly process of pretreatment. The reason of different pretreatments leading to different deposition rates on magnesium alloy was clarified by open circuit potential-time curves. The surface morphology, chemical composition and structure of these coatings were characterized using SEM, EDX and XRD. The results show that all of these nickel coatings have high P content (about 11%), similar surface morphology and structure. Polarization curves indicate that the coatings obtained by H3PO4+HNO3 pickling, K4P2O7 and NH4HF2 activation separately, possess slightly stronger corrosion resistance than the traditional chromic acid methods. The new pretreatment bring about etched deep cavities, which increase the mechanical occlusive force between the coatings and the substrate. Thus, the adherence between the coating and the substrate is improved ultimately.

• 出版日期2016-1
• 单位西华师范大学