Predictive power for life and residual life of the zinc rich primer coatings with electrical measurement

Zinc rich primers with lamellar and spherical shaped zinc pigments and their combinations were formulated. These zinc rich primers were used to measure the electrical conductance and subjected to the corrosion analysis for 3000 h. The lamellar shaped pigments at lower PVC were found to be better than spherical shaped pigments, whereas the typical combination of spherical and lamellar zinc was the best in providing corrosion protection. A set of equations were developed to predict the life and residual life for pigment of both shapes using PVC, conductance and corrosion resistance for 3000 h in salt spray as parameters. Finally the influence of zinc particle shape on the flow and orientation behavior was evaluated using rheological measurements.