Tribological investigation of shot peened NiP-CN electroless coating on EN31 steel

The present study is focused on the investigation of tribological, mechanical and microstructural properties of the Electroless Nickel Phosphorus and Cenosphere coating carried out over the shot peened EN 31. The aim of the current study is to reduce the failure and increase the life time of machining parts in terms of improving the surface and frictional properties of materials. Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals to improve the fatigue strength and provide the plastic deformation. In this research shot peening process is carried out on the EN31 steel substrate followed by the Electroless NiP/Cenosphere (CN) coating to improve the corrosion and wear resistance. Electroless coating processed under various composition of cenosphere. The pin on disc wear analysis has been demonstrated over the coated specimen for various loading conditions. Vickers Micro hardness results shows that the hardness of the NiP coated specimen with 1.5grams of cenoshpere has doubled compared to the uncoated EN31 specimen. The wear and friction results shows that the substrate with 1.5gms of cenosphere has low coefficient of friction compared to other compositions. The worn surface analysis has been carried out using the optical microscope.