Investigation of the effect of physical conditions of a coating bath on the corrosion behavior of zinc coating using response surface methodology

In this study, to minimize the corrosion rate zinc coatings conditions were optimized using a Box-Behnken design combined with response surface methodology. The different electro zinc coatings were obtained by changing three independent variables; the stirring rate (200–600 rpm), temperature of the bath (30–70°C) and the coating time (30–120 min) in 3.5% NaCl solution. The corrosion rate of the obtained zinc coatings was determined using the Tafel polarization method. A quadratic regression equation was derived to predict the responses. The correspondence between the experimental and predicted values (R(adj)2 = 98.55%) demonstrates that the quadratic model was highly significant with 95% confidence levels (α = 0.05). The optimum zinc coating conditions based on the minimization of corrosion rate were; stirring rate 600 rpm, temperature of bath 55°C and a coating time of 50 min for icorr 16.35 μA/cm2.