This work contributes to the development and characterization of the corrosion resistance and antifriction properties of high performance polyurethane (PU)/graphene (Gr) composite coating. In this study, PU composite coatings containing 0, 2, 4 and 8 wt.% of Gr were prepared and evaluated using various corrosion and mechanical tests, namely electrochemical impedance spectroscopy, salt spray tests, cross-cut tape tests and dynamic mechanical analysis. Antifriction properties of the coatings were evaluated using a tribometer with a ball-on-disc mode at room temperature. The corrosion resistance and adhesion property of the PU coatings were found to be enhanced by adding 4 and 8 wt.% of Gr. The coefficient of friction revealed that the antifriction properties of the PU/Gr composite coatings were 61% lower than those of the conventional coating when the Gr content was increased to 8 wt.%.

This study investigated the corrosion properties of a Fe ₅₀ Mn ₃₀ Co ₁₀ Cr ₁₀ dual-phase high-entropy alloy (DP-HEA) in 0.1 M H ₂ SO ₄ aqueous solution. The observed corrosion properties of the DP-HEA were compared with those of an equiatomic CoCrFeMnNi high-entropy alloy (HEA). Moreover, a passive film formed on the surface of the DP-HEA in an acidic environment was directly imaged and characterized for the first time through high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Both alloys exhibited typical active–passive behaviors in the potentiodynamic polarization test and presented similar passive current densities. The HR-TEM results revealed that the anodic passive films formed on the surfaces of the two alloys had similar thicknesses (3–5 nm). However, potentiodynamic polarization measurements showed that the DP-HEA had a higher corrosion current density and lower corrosion potential than did the HEA. XPS revealed that the anodic passive film formed on the DP-HEA contained a lower ratio of Cr ₂ O ₃ /Cr(OH) ₃ , which led to poor corrosion resistance properties, as demonstrated by the potentiodynamic polarization measurements and electrochemical impedance spectroscopy.

Biocides are frequently used to control sulfate-reducing bacteria (SRB) in biofouling. The increasing restrictions of environmental regulations and growing safety concerns on the use of biocides result in efforts to minimize the amount of biocide use and develop environmentally friendly biocides. In this study, the antimicrobial activity and corrosion inhibition effect of a low-toxic alternative biocide, benzyldimethyldodecylammonium chloride (BDMDAC), on a 304 stainless steel substrate immersed in a Desulfovibrio desulfuricans (D. desulfuricans)-inoculated medium was examined. Potentiodynamic polarization curves were used to analyze corrosion behavior. Biofilm formation and corrosion products on the surfaces of 304 stainless steel coupons were examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectrum, and confocal laser scanning microscopy (CLSM). Results demonstrated that this compound exhibited satisfactory results against microbial corrosion by D. desulfuricans. The corrosion current density and current densities in the anodic region were lower in the presence of BDMDAC in the D. desulfuricans-inoculated medium. SEM and CLSM analyses revealed that the presence of BDMDAC mitigated formation of biofilm by D. desulfuricans.