Exploring salt-mist corrosion resistance of GPTMS functionalized graphene oxide reinforced epoxy resin composite coating on shot-peened Ti-15333 titanium alloy

The purpose of this work was to research the effects of 3-Glycidyloxypropyltrimethoxysilane (GPTMS) incorporation and shot peening on the salt-mist corrosion resistance and adhesion property of GO-epoxy coating over Ti-15333 alloy. Herein, in order to increase the adhesion strength between the organic coating and the metal matrix, the surface roughness of Ti-15333 alloy was improved by the shot peening technology, and graphene oxide (GO) could reduce the micro defects in the epoxy resin matrix to enhance anti-corrosion properties. In addition, the coating was doped with GPTMS to improve active corrosion protection. The treated Ti-15333 alloy's corroded surface has been characterized by SEM, EDS and XPS techniques. The barrier capabilities and adhesion efficiency of different protective layers were further analyzed by polarization curve, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) tests. According to the fitting results of the polarization curve, after 312 h of salt-mist, the corrosion current densities of the GO-epoxy and f-GO-epoxy coating samples were 2.692 × 10−7 and 3.990 × 10−8, respectively, the calculation result showed that their protection efficiency reached 63.76% and 94.63%, respectively. Meanwhile, according to the EIS and EN results, f-GO-epoxy coating sample's corrosion protection properties increased significantly. The pull-off results showed that the f-GO-epoxy coating had the most significant increase in adhesion strength compared to the GO-epoxy coating sample. The results reveal that the synergistic effect of GPTMS incorporation and shot peening significantly enhance the corrosion resistance and adhesion strength of GO-epoxy coating over Ti-15333 alloy.