Electro and Electroless Deposition of Nickel and its Alloys from Different Electrolytic Baths

Abstract

Introducing nickel alone or with other metals by electro- or electroless deposition significantly affect the properties of the substrate surface. The use of gluconate as complexing agents through this research because of its cheap, non-toxic, easily obtained and its degradation products offer easier treatment. Electro and electroless deposition of nickel from gluconate bath was studied; the coatings obtained were characterized using different techniques such as SEM, EDX, X-ray diffraction, thickness, hardness and corrosion resistance. Electrodeposition of nickel from additives free, gluconate bath and in presence of aniline sulfate, chloramine B, and urea as additives improved the mechanical and corrosion resistance of the copper substrate the corrosion resistance for the deposits from the above bathes was 6.3, 2.7, 12.2, 3.5 and 72.4 μm/Y, respectively. The electrodeposition of Co–Ni alloys is anomalous codeposition type. The less noble metal, Co, deposits preferably to the nobler one, Ni. The operating conditions such as current density, temperature, pH, concentration of all solution components, etc. lead to changes in the kinetics of electrodeposition, the composition and morphology of the coatings and their physicomechanical characteristics. Nanocomposite coatings were obtained by electrochemical codeposition of Al2O3 or TiO2 nano-particles mean diameter70, 50 nm respectively with nickel, from the gluconate bath. The electrodeposition of the embedded nano-particles in nickel matrix, as a function of pH, current density and concentration of particles in the bath were studied. The observed results of composite coatings are associated with specific structural modifications of Ni crystallites and mechanical properties. The electroless deposition of binary Ni-P, Ni-P-W ternary alloys and Ni- P-(Al2O3 or TiO2) nanocomposite was investigated. The influence of different operating conditions on coatings performance was studied. The obtained coatings show great variations, in structures, and mechanical properties of nickel matrix.