Predicting electroless Ni-Co-P coating using response surface method

Electroless Ni-Co-P coating has been studied considering pure copper (99.99 %) as a substrate material. The deposited mass per unit area of the substrate has been considered as the response variable. The individual as well as combined effects of the process parameters on the response variable has been studied. The bath temperature and the interaction of cobalt source concentration and reducing agent concentration have been found to be significant through regression analysis and Student's t test. Mathematical modelling has been carried out using a second-order response surface model with central composite design to take into account the effect of curvature in the predicted response. The equation for response surface has been determined using MATLAB software package. The response surface plots show that the rate of deposition increases significantly with the rise in temperature while the cobalt source concentration and reducing agent concentration have an interactive effect which influences the rate of deposition. The test of reliability for the predicting response surface equation shows that the equation gives an excellent fitting to the observed values.