Influence of embedded reduced graphene oxide on the corrosion-wear performance of cold sprayed Zn-rGO/Al coating in NaCl solution

Zn-Al coating is an excellent cathodic protection coating to provide corrosion protection for carbon steel. However, low hardness coating will accelerate abrasion under the erosion of sea water. To enhance the anti-wear property of Zn-Al coating in sea water, the self-lubricating Zn-xrGO/Al composite coatings (x is the content rGO on Al powders =0.1 wt%, 0.2 wt%, 0.3 wt%) were deposited on low carbon steel by using a low-pressure cold spraying technique. The microstructure and mechanical property for the composite coatings were detected. The corrosion-wear performance for the composite coatings as a function of rGO concentration on Al powders was investigated by analyzing the friction behavior in 3.5 wt% NaCl solution. When the rGO concentration on Al powders is 0.2 wt%, the obtained Zn-0.2 wt% rGO/Al coating has the highest hardness which is enhanced by 20% compared with Zn-Al coating. When worn in NaCl solution, Zn-0.2 wt% rGO/Al coating exhibited the best self-lubrication property with recurrent forming of a lubrication platform with low COF value of 0.22. The formation of the lubrication platform can be attributed to the synergy action of the friction heat and anodic polarization effect provided by the highly electronegative rGO, which promotes the formation of corrosion products layer and makes up the consumption of lubrication film.