The rust preventing mechanism of zinc dust paints

In atmospheric weathering the rust preventing mechanism of zinc dust paints is dominated by the sealing action of the zinc corrosion products on the paint surface. Under immersed conditions the time of cathodic protection of bare steel is dependent on the zinc content of the paints. An optimum zinc content has been found for all of the tested binders: polystyrene, vinyl copolymer and chlorinated rubber. Differences in the optimum zinc content arise mainly due to the different wetting of the pigment by the binders.