Advanced Ni-W coatings obtained by the combination of pulse plating and chemometric techniques

The electroplating of Ni-W alloys could represent one of the most promising environmentally friendly alternatives to replace hard chromium. However, the Ni-W process and coatings still show some limitations such as lower hardness than hard chromium and limited corrosion resistance that need to be overcome in order to be considered a real solution. In this work, a Ni-W electrolyte was proposed and optimised. A chemometric approach was used in order to design pulse plating experiments and study the effect of experimental parameters on the properties of pulse plated Ni-W coatings. In addition, multivariate analysis was proposed to establish a relation among structural and physical characteristics of Ni-W deposits, and the optimum values of the process parameters required to improve their properties were determined. Results indicate that by the combination of pulse plating and chemometric techniques, Ni-W coatings with improved uniformity, efficiency and hardness compared to those obtained by direct current could be obtained, achieving hardness and corrosion resistance values similar to those of hard chromium coatings.