A water-based coating composition containing two parts A and B: (A) a binder component containing a waterborne epoxy dispersion, dispersed inorganic particles, and a polymeric dispersant; and (B) a hardener component, and a ratio of the component (A) and the component (B) is 90:1 to 2:1. The polymeric dispersant contains anti-agglomerating functional groups that are unreactive with oxirane groups of the epoxy dispersion.