Effects of Surface Modification and Heat Treatment on the Storage and Application Properties of Waterborne Zinc-Based Paint

Abstract

The high activity of metallic zinc particles with water, and consequently the short pot lift of a mixed waterborne organic zinc-rich paint, are the most well-known problem for their application. In this study, zinc powders were modified by silane-crosslinked potassium silicate and the paint’s pot life was prolonged. Electron microscopy analysis showed that the zinc spheres in the waterborne paint were encapsulated by the shell consisted of silane-crosslinked potassium silicate and resin. The modification allowed the paint stay fluid after storage for 36 h. Nevertheless, the thickened shell was found to deteriorate the cathodic protection provided by the zinc particles. As a repair strategy, the post-heat treatment performing on the coating could awaken the protective effect of zinc powders. The anti-corrosion performance of the repaired coatings was confirmed by electrochemical tests and salt spray tests.