The present invention provides a method for improving corrosion resistance of a metal substrate. The method comprises the steps of (a) electrophoretically depositing a curable electrodepositable coating composition on the substrate to form a coating over at least a portion of the substrate, and (b) a temperature sufficient to cure the coating on the substrate. Heating the substrate for a period of time. The electrodepositable coating composition includes a resinous phase dispersed in an aqueous medium, wherein the resinous phase comprises: (1) a resin containing non-gelling active hydrogen, which can be electrodeposited onto the cathode, containing a cationic salt group; (2) at least partially blocked polyisocyanate curing agent; And (3) a pigment component comprising an inorganic platelike pigment having an average equivalent spherical diameter of at least 0.2 microns. The electrodepositable coating composition exhibits a ratio of pigment to binder of at least 0.5. The coating composition contains less than 8% by weight of the ground vehicle.
展开▼
