Abstract: A low volatile organic content hybrid silica binder, with a total silica content of about 29% to about 42% by weight, suitable for use in the manufacture of zinc-rich primer coating compositions is disclosed. The binder comprises a predominant amount of a silica component derived from the hydrolysis of an organic silicate and a lesser amount of a silica component derived from a sillica sol. The solvent component comprises no more than about 75% by weight of an organic solvent having a volatility equal to or greater than the volatility of a C.sub.1 to C.sub.3 alkyl monohydric alcohol and about 25% by weight or more of a solvent having a lesser volatility than the volatility of a C.sub.1 to C.sub.3 alkyl monohydric alcohol, with the condition that no more than about 90% by weight of such lesser volatile solvent is a butanol.

Abstract: A binder composition is prepared by hydrolyzing and condensing an organotrihydrocarbonoxy silane in excess water, and thereafter combining this composition with particulate solids, to form a coating composition for metal surfaces which will impart galvanic protection thereto.