Electrodeposition of nickel/SiC composites in the presence of cetyltrimethylammonium bromide

Electrodeposition of SiC particles with nickel matrix in the presence of cetyltrimethylammonium bromide (CTAB) at two current densities was carried out. Surface chemistry (amount of acidic and basic superficial groups, surface charge, Ni2+ and Br− adsorption) of the SiC powder in the presence of various CTAB amounts (0-1.1 mM) was studied. Cationic surfactant inhibited adsorption of cations and enhanced adsorption of anions on the positive charged carbide surface, but Br−/Ni2+ molar ratios for adsorbed ions were higher than in the bath. It was attributed to the CTAB adsorption realized predominantly by hydrophobic interactions between aliphatic chain of the molecule and SiC surface with the positive head group of CTA+ pointed toward the bulk solution. Increased SiC incorporation to the composite coating with CTAB addition was observed. Correlation between current efficiency and Br−/Ni2+ molar ratios for ions adsorbed on SiC was found. The influence of CTAB concentration on the cathodic polarization curves was also determined. Structure of the composite coatings was studied by microscopic observations. Microhardness of the fine-grained metal matrix composites was also determined.