Synthesis and Characterisation of Metallic Coating by Pulsed DC

Abstract

Metallic coating is given to provide a layer of protection to metals or other types of materials that are subjected to various harsh operating conditions like high temperature, contact surfaces, corrosive media, high stress and other surface degrading conditions. These coatings help to enhance the reliability and performance of industrial. These coatings are used in industries such as aerospace, defense, military and automotive. Some of the most common metallic coatings that can be applied to substrate are Zn, Cu, Cd, Ni, Zn and Au. In this project Nickel coating was given to mild steel substrate as Nickel gives a anti corrosive coating to the steel surface and also enhances the hardness value of the surface. Nickel is now extensively used in industrial applications for Decorative as well as Engineering purposes because of its bright appearance and resistance to corrosion property. Nickel deposition was carried out using Watts Bath and deposition was carried out by electrodeposition method. Electrodeposition is the fastest and simplest method of providing coating to any substance. Deposit characteristic can be modified by changing various operating parameters like current density, temperature and pH of the solution. Use of pulse DC gives more control over the microstructure and morphology of deposit. Ten different samples were given coating, one used as reference sample was given coating in presence of DC and others using pulsed DC. In case of pulse DC three different parameters can be varied to give different features to deposit namely peak current, TON and TOFF. Finer grains can be obtained using pulse DC. After the deposition completed, the coating was characterizes by XRD, SEM and hardness measurement.