Edge protection improvement of automotive electrocoatings in the presence of silica nanoparticles

The present study develops a method for edge coverage improvement of the cathodic electrocoatings by silica nanoparticles. The effect of silica nanoparticles on the rheology of curing process, anti-corrosion performance, edge protection, and morphology are studied. Field emission scanning electron microscopy (FE-SEM) is utilized to investigate the dispersion of nanoparticles in the coating matrix. The anti-corrosion performance is studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. Rheometric mechanical spectrometer (RMS) and dynamic mechanical thermal analysis (DMTA) are used to investigate the rheology of the curing process and curing behavior of the coatings respectively. Minimum melt viscosity has increased significantly in the presence of the 4 wt% nanoparticles. Results show significant improvement of edge coverage in presence of the 4 wt% nanoparticles.