Effects of Different Surfactants on Structural, Tribological and Electrical Properties of Pulsed Electro-Codeposited Cu-ZrO₂ Composite Coatings

Cu-ZrO₂ composite coating was synthesized by pulse electrodeposition from an acidic sulfate electrolyte dispersed with nano-sized ZrO₂ particles. Effects of different surfactants in different amounts on the codeposition and distribution of ZrO₂ particles in the copper matrix, surface-mechanical (hardness and wear) and electrical (conductivity) properties of developed composite coatings have been thoroughly investigated. Sodium dodecyl sulfate (SDS), poly acrylic acid (PAA) and glucose have been added in the electrolyte in different concentrations as anionic, polymeric and nonionic surfactants. Obtained experimental results confirmed that addition of SDS up to 1 g/L improves the amount of codeposited ZrO₂ particles in the copper matrix and surface-mechanical properties of the nanocomposite coatings. But, in case of PAA- and glucose-assisted coatings, highest amount of ZrO₂ codeposition was observed in 0.5 g/L PAA and 20 g/L glucose-assisted coatings, which in turn affected the mechanical properties. Surface-mechanical properties were found to be affected by coating matrix morphology and crystallographic orientation along with embedded ZrO₂ particle content. Electrical conductivity of all the deposits not only depends upon the codeposition of ZrO₂ particles in the matrix but also on the microstructure and crystallographic orientation.