Corrosion resistant substrate with metallic undercoat and chromium topcoat
First Claim
1. A coated metal substrate having enhanced corrosion resistance and protected by a coating composite comprising a thin metallic undercoating layer of combined metals in metallic form at least one of which is selected from the group consisting of zinc, nickel, iron, chromium, aluminum and cobalt, and a heat-curable, substantially resin free, as well as phosphate free, topcoat layer from composition curable to a water resistance protective coating, said topcoat layer being free from particulate metals while containing above 10 milligrams per square foot of coated metallic undercoating of chromium, as chromium, in non-elemental form, said composition containing hexavalent-chromium-providing-substance in liquid medium.
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Accused Products
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.
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Citations
33 Claims
- 1. A coated metal substrate having enhanced corrosion resistance and protected by a coating composite comprising a thin metallic undercoating layer of combined metals in metallic form at least one of which is selected from the group consisting of zinc, nickel, iron, chromium, aluminum and cobalt, and a heat-curable, substantially resin free, as well as phosphate free, topcoat layer from composition curable to a water resistance protective coating, said topcoat layer being free from particulate metals while containing above 10 milligrams per square foot of coated metallic undercoating of chromium, as chromium, in non-elemental form, said composition containing hexavalent-chromium-providing-substance in liquid medium.
- 16. A coated metal substrate having enhanced corrosion resistance and protected by a coating composite comprising a thin metallic undercoating layer containing zinc and nickel in alloy form and a heat curable, substantially resin free, as well as phosphate free, topcoat layer from composition curable to a water resistant protective coating, said topcoat layer being free from particulate metals while containing above 10 milligrams per square foot of coated metallic undercoating of chromium, as chromium, said composition containing hexavalent-chromium-providing-substance in liquid medium.
- 31. A coated metal article in sheet form having on one or both faces of said formed article a thin metallic undercoating layer of combined metals in metallic form at least one of which is selected from the group consisting of zinc, nickel, iron, chromium, aluminum and cobalt, while further having on one or both faces of said formed article a heat curable, substantially resin free, as well as phosphate free, topcoat layer from composition curable to a water resistant protective coating, said topcoat layer being free from particulate metals while containing about 10 milligrams per square foot of coated metallic undercoating of chromium, as chromium, in non-elemental form, said composition containing hexavalent-chromium-providing-substance in liquid medium.
Specification