<p>During underwater repair of failed marine equipment coatings, the presence of residual liquid between the repair coating and the substrate will weaken the interfacial adhesion. This decrease in adhesion properties significantly impacts on the mechanical properties, tribological properties, and corrosion resistance of the repair coating. This study designed GO-Fe₃O₄ hybrid fillers and prepared the GO-Fe₃O₄/ER composite coating. The hybrid fillers drive the uncured ER matrix to squeeze out the residual liquids, by an external magnetic field. The optimal content of GO-Fe₃O₄ hybrid fillers is 1.5&#xa0;wt.%, and the effect of the hybrid fillers on the mechanical properties was investigated. The reinforcing and lubricating phases synergistically enhance GO-Fe₃O₄/ER composite coatings to exhibit optimal tribological properties. The influence of the preparation process with/without magnetic field, filler type, and filler content on the corrosion resistance of the ER composite coating was investigated. The synergistic effect of magnetic polymorphic filler enhances the corrosion resistance of GO-Fe₃O₄/ER composite coating, where the magnetic field preparation process excludes residual liquid, and the polymorphic filler hinders the penetration of corrosive media. The magnetic hybrid filler reinforced ER coating has application potential in the underwater repair of marine parts.</p> Graphical abstract <p></p>