Wear, Corrosion and Tribocorrosion Behavior of Polyurethane and Polyvinylpyrrolidone Blends as Coating for Corrosion Protection of AISI 316L Stainless Steel

Polyurethanes (PUs) are used across a widely from biomaterials to industrial applications due to their versatile properties. Polyurethane is blended with other polymers to improve their physical and thermal properties. In this study, different concentrations of polyurethane and polyvinylpyrrolidone (PVP) blends were applied to AISI 316L stainless steel using the dip coating method as protection against wear and corrosion. The effects of different concentrations of blends on the mechanical, corrosion and tribocorrosion properties of the AISI 316L stainless steel were investigated. The phase structure of polymer coatings were investigated by X-ray diffraction (XRD), and their surfaces were examined by scanning electron microscopy (SEM). Corrosion and tribocorrosion tests of the polymer coated samples were carried out in 3.5% NaCl solutions. The surface roughness and nanohardness of the polymeric coated samples were also measured. It was found that surface roughness and friction coefficient increased with raised concentration of PVP, while wear and corrosion resistance decreased with the increased of PVP concentration in the coating. As the penetration depth of the PU coated sample increased, the nanohardness and elasticity modulus decreased. Coatings containing PVP up to 25% protected the substrate surface under tribocorrosion conditions in NaCl solutions.