Effect of Coating Time on the Performance of Electroless Nickel Coated Steel

Electroless Nickel (EN) coatings are used in automotive application due to its high hardness, uniform thickness and wear resistance. The study deals with the improvement of surface properties of mild steel by the deposition of Ni-P alloy. The steel specimens were EN coated for various time duration ranging from 0.5 to 3 h. The effect of coating time on thickness, structure, hardness and wear of EN coated steel are investigated. It has been found that the coating thickness is uniform and it increases as the coating time increases. There is no significant change in hardness and wear with increase in coating time. The structure of EN coated steel comprises a surface layer of Ni-P alloy deposit which is instrumental in increase in the hardness. Microhardness of EN coated steel is in the range of 500-540 Hv_0.025. The wear rate and coefficient of friction of EN coated steel is found to be low compared to the base metal. EN coated steel could be of use for improving the performance and life of various automotive components.