Optimization of electroless Ni-P coating bath and its impact in the Industrial Applications

Abstract

Electroless Ni-P coating is widely used in industrial engineering applications due to its ability to alter and improve the surface properties of the steel substrate. Electroless nickel coating introduce an excellent combination of surface properties. It can add brightness, lustre, and appeal. The final coating layer also possess very good adhesion with coated substrates, this is the reasons for using such layer as an 'undercoat' for other coatings. The ability to produce a very homogenous composition and produce coating with high corrosion resistance are mainly based on the plating bath composition. The present work investigates the influence of bath compositions, which included nickel sulphate, sodium hypophosphite and tri-sodium citrate, on the process of electroless Ni‒P coating. The deposition rate (Dr) as well as the bath stability were monitored to optimize the plating bath conditions with the different composition. The results of this work showed that the deposition rate of coating layer increase with increase of nickel source and reducing agent while; sodium citrate concentration in the plating bath have adverse effect on the deposition rate of coating.