The performance of surfactant on the surface characteristics of electroless nickel coating on magnesium alloy

Magnesium and its alloys corrode rapidly in the electrolyte bath. Surfactants while used extensively as surface active agents in the electrolyte bath, have been little studied on magnesium surfaces. The influence of surfactants cetyltrimethyl ammonium bromide (CTAB) and sodium lauryl sulfate (SLS) on the surface properties such as roughness, morphology and topography of electroless Ni–P deposits on magnesium alloy was researched. The research reveals that the surfactant solutions has significant influence on the composition of coating, surface roughness and surface morphology. In addition, it has marginal effect on the microhardness. Electroless coatings with addition of surfactants produce a smooth surface and average roughness value of 1.412 μm for CTAB and 1.789 μm for SLS, which are less than the value (2.98 μm) without surfactant addition. There was a significant improvement in the rate of deposition. However, the surfactants influence reached maximum at critical micelle concentration and above this value it gets stabilized. The initial structure appears to be dependent upon the percent occluded surfactants. The surface microstructures are discussed in line with the experimental observations.