Abstract: A coating composite provides extended corrosion resistance for substrate metals. The thin metallic undercoat of the composite contains combined metals. The heat curable and substantially resin free topcoat is established from composition containing chromium in non-elemental form, which topcoat composition may further contain particulate metal, all in liquid medium. In addition to outstanding corrosion resistance, the composite can retain substrate weldability as well as achieving formability, while further enhancing paintability and weatherability.

Abstract: A coating composite provides extended corrosion resistance for substrate metals. The thin metallic undercoat of the composite contains combined metals. The heat curable and substantially resin free topcoat is established from composition containing chromium in non-elemental form, which topcoat composition may further contain particulate metal, all in liquid medium. In addition to outstanding corrosion resistance, the composite can retain substrate weldability and formability, while further enhancing paintability and weatherability.

Abstract: A chromium-containing coating composition, also containing pulverulent metal, will provide a coating of excellent corrosion resistance when the composition contains urea as at least a part of the reducing agent, and when the composition also contains particular pH adjusting agent. The reducing agent of the composition is used in regard to the hexavalent chromium contained in the chromium portion of the composition. The pH adjusting agent should be a compound of zinc. In addition to achieving excellent corrosion resistance, resulting coatings can provide the other desirable characteristics for coated substrates, such as topcoat adhesion and formability, without deleterious effect.

Abstract: A coating composition for application to a metal substrate can desirably contain CrO.sub.3 and zinc flake in aqueous medium, as well as containing organic liquid. Such compositions will provide a corrosion and alkali resistant coating to the metal. The zinc flake can be mechanically flattened from non-flake starting material, in a liquid medium that includes organic liquid for the coating composition. Efficiency of compositional preparation initiating with flake preparation is thereby achieved.

Abstract: Metal treating compositions, containing chromic acid and pulverulent zinc, and which find particular utility in the coating of metal substrates prior to painting, now exhibit extended bath stability through pH adjustment. The key to the adjustment is not in the final bath makeup. Rather, the adjustment is made during preparation of a precursor component containing chromic acid. Such component of adjusted pH may then be blended with additional composition ingredients including the pulverulent zinc to form a bath of excellent stability, e.g., extended freedom from gelation.