Electroless NiP-TiO2 sol-RGO: A smart coating for enhanced corrosion resistance and conductivity of steel

Abstract

Nickel phosphorus – titanium dioxide sol – reduced graphene oxide (NiP-TiO2 sol-RGO) coating was firstly prepared by using a simple one-pot electroless plating to effectively improve both corrosion resistance and conductivity of steel. Initially, titanium dioxide sol (TiO2 sol) was synthesized via sol-gel method and then used to intercalate between graphene oxide (GO) nanosheets for increased GO dispersion and loading prior to electroless deposition. The parameters controlling the coating appearance and property, (e.g. amount of TiO2 sol, electroless plating time and amount of GO) were systematically optimized. The as prepared NiP-TiO2 sol-RGO and the coated steel surface morphologies were characterized by transmission electron microscopy and scanning electron microscopy. The hydrophobicity, corrosion resistance and conductivity of the coated steel were examined by contact angle measurement, electrochemical testing and four-point probe conductivity measurement, respectively. NiP-TiO2 sol-RGO coated steels show high homogeneity coating with ultra-thin water-repellent RGO layer fully covering on the outer surface leading to significant improved corrosion resistance and electrical conductivity of steel. These promising properties of the coating might be very useful for electronic part applications, which requires both high corrosion resistance and high conductivity with less sensitive to humidity, such as electronic parts and electrode for electrochemical sensors.