Experimental investigations and effects studies on electrodeposited Ni-Cr composite coating using robust design approach

Abstract

Electrocodeposition is acknowledged as superior technique for preparation metallic and alloy based composite coatings with enhanced properties. In this study an attempt has been made to deposit micron sized chromium particles in nickel matrix by electrocodeposition principles. The electrocodeposition setup is established and the composite coatings are prepared from watts type nickel bath. The experiments are framed by robust experimental design of Taguhci’s orthogonal array approach. The process parameters are considered for study and the L27 orthogonal array is chosen for experimental design. The Ni-Cr composite coatings are prepared over mild steel substrates. The outcomes, mass of deposit, area fractions of particles and microhardness of particles are evaluated methodically. The presence of Cr particles in nickel matrix is examined with SEM, XRD and EDS studies. The direct effects of electrodeposition process variables on microhardness of Ni-Cr thin film coatings are investigated with signal to noise ratio, mean effects and analysis of variances. Base on the significances the parameters are ranked by order. It has been revealed that current density has the predominant effects on microhardness of Ni-Cr and authenticated with scientific and statistical investigations. Regression model is developed for prediction of the microhadness of Ni-Cr coatings and the predicted values are well associated with experimentation outcomes.