Response surface analysis of Zn–Ni coating parameters for corrosion resistance applications: a Plackett–Burman and Box–Behnken design of experiments approach

Abstract The development of cost-effective coatings with exceptional corrosion resistance is an ongoing challenge in the field of materials science. Among the promising coatings, zinc–nickel (Zn–Ni) coatings have shown great potential, especially when produced using economical electroplating technology. However, achieving optimal performance while minimizing coating thickness remains a complex task. In this study, the behavior of the responses was investigated according to the coating standards and levels, focusing on eight variables including temperature, time, cathodic current density, nickel concentration, substrate hardness, roughness, cathode–anode distance, and magnetic stirring speed. Four responses were investigated: coating thickness, roughness, microhardness, and corrosion rate with potentiodynamic polarization, using two design of experiments (DOE) methods: Plackett–Burman design (12 runs) and response surface methodology with Box–Behnken design (15 runs). The results show the degree of influence of each variable on the responses and their contribution to changing the responses. Additionally, response surfaces have been determined and it is shown that large response values can be achieved with small thicknesses. The morphological study using SEM, EDX, and XRD techniques revealed that the deposition conditions play an important role in the surface morphology. Some samples showed microcracks, while others had small grain size and were free of cracks and pores. Overall, this study provides new insights into the improvement of Zn–Ni coatings with exceptional corrosion resistance and cost-effectiveness.