Enhancing cathodic protection and barrier properties of zinc-rich epoxy coatings with mesoporous Ti4O7 additive

Searching for an optimal material additive that can enhance both the cathodic protection and barrier properties of zinc-rich epoxy coatings (ZRE) simultaneously remains a significant challenge nowadays. In this study, mesoporous Ti 4 O 7 particles with high conductivity and chemical inertness were synthesised via the thermal reduction method and added to ZRE coating. The impact of different Ti 4 O 7 filler contents on the corrosion resistance of ZRE coating containing 70 wt% zinc was assessed by electrochemical analysis , water uptake measurements, salt spray test and material characterisation techniques . The results demonstrated that the incorporation of mesoporous Ti 4 O 7 significantly enhances the initial cathodic protection and long-term barrier properties of ZRE. The primary mechanism involves the conductive Ti 4 O 7 ameliorating the Zn isolation caused by non-conductive Zn corrosion products and fostering a more efficient network for conductive penetration between zinc particles to improve cathodic protection efficacy. Moreover, mesoporous Ti 4 O 7 promotes the uniform deposition and growth of ZnO/Zn(OH) 2 by adsorption and anchoring of Zn(OH) 4 2− and changes the shape of the corrosion product (columnar), thus improving the barrier performance of ZRE coating.