A study of nickel electroplating onto magnesium alloy

Abstract

Electroplating of nickel onto magnesium alloys surface by using nickel sulphate solution as the electrolyte solution. This study was done to study the effect of different voltages (1V – 5V) used after nickel electroplating process onto the surface of magnesium alloy. Other than that, this study was done to investigate the properties of nickel coating on Mg alloy in terms of thickness, hardness and microstructure. The surface of magnesium alloy was firstly ground and polished to remove oxide layer and foreign matters. Nickel ions was plated onto the surface of the sample by electroplating process for 20 minutes with different voltages. After electroplating process, a blue-greenish layer was deposited on the magnesium alloy surface. The samples was analysed by the weight gained percentage, optical microscope (OM), Scanning Electron Microscope (SEM) and Vickers Hardness testing. The result from OM and SEM shows the uniformity, thickness and microstructure of nickel plated onto the surface of the magnesium alloy. The hardness value also was obtained from hardness test. The result from this research indicates that the higher the voltage causes the hardness value to increase. Besides that, the increases of voltage produced good thickness of nickel plated onto magnesium alloy surface. The thickness of coating layer also increase when voltage increase. However, as the thickness of the nickel plated increases, it is not uniformly plated on the surface of plated sample. Other than that, as the nickel electroplating reached the optimum voltage, the percentage of weight gained decreased.