The influence of SDS and CTAB surfactants on the surface morphology and surface topography of electroless Ni-P deposits

The effect of surfactants sodium dodecyl sulphate (SDS) and cetyltrimethyl ammonium bromide (CTAB) on the surface roughness, surface morphology and surface topography of electroless nickel (EN)-phosphorus surface protective coating obtained from an alkaline bath is presented in this paper. in this study the influence of surfactant concentrations on the surface roughness of coated samples were investigated. It was observed that the surface roughness, surface morphology and surface topography of Ni-P coating were clearly influenced by the addition of surfactants SDS and CTAB. EN deposits with addition of surfactant SDS and CTAB at a concentration of 0.6 g/l produce a smooth surface and the average roughness (R-a) value is 1.715 mu m for SDS and 1.607 mu m for CTAB which is less than the R-a value of EN deposit without surfactant addition (1.885 mu m). The mean average roughness (R-a) value with addition of surfactant is 1.796 mu m. EN deposit with addition of surfactants consists of a significant fraction of particles of nickel. in the presence of SDS, fine nickel particles have dispersed uniformly on the substrate surface resulting in smoother surface finish of the deposited layers. In the presence of CTAB, at lower concentrations (upto 0.6 g/l) coalescence of nickel particles have been deposited on the substrate surface and at the higher concentration (above 0.6g/l) uniformly improved surface finish of the deposited layer is resulted. The complete experimental details, results obtained and their analysis are presented in this paper. (C) 2008 Elsevier B.V All rights reserved.