MAIN FACTORS THAT INFLUENCE CORROSION RESISTANCEOF AUTOCATALYTIC NICKEL-PHOSPHORUS

摘要

The goal of this study is to identify the main factors that influence corrosion resistance of autocatalyticnickel-phosphorus (NiP) coatings. The considered factors were: substrate type, substrate surface finishing,bath age, phosphorus content, thickness, heat treatment and impurities. Initially, the selection of the mainfactors was made through a fractional factorial design. During the NiP characterization tests, it wasverified that the selected coatings were not produced accordingly to the design previously established. Forthis reason, the analysis of the obtained results was made based on the best subset regression. Thecorrosion resistance of the selected coatings was verified through Salt Spray and Kersternich tests. Thesubstrate type, the bath age, the thickness, the heat treatment, the phosphorus content as well as sulfur,lead, magnesium, copper, iron and manganese impurities are the main factors that influence the NiPperformance.