Parametric optimization and prediction of electroless Ni–B deposition

The alkaline borohydride-reduced bath has been used to deposit electroless nickel–boron (Ni–B) coatings on a pure (99.99%) copper substrate. The electroless Ni–B deposition per unit area has been considered as a response variable and response surface method has been used to optimize the process parameters and the response. Initially, a first order response surface model has been considered and steepest ascent method has been used to reach in the vicinity of optimal region of the response surface and subsequently, a second order response surface model with central composite design (CCD) has been used to take into account the curvature around the optimal region. The predicting response surface equation has been determined by using MATLAB software package and the optimal values of process parameters have been determined for maximum deposition per unit area. The three-dimensional surface and contour plots shows the variation Ni–B deposition with different process parameters. F-test for the predicting response surface equation confirms that the equation gives an excellent fitting to the experimentally observed data.