Oxide coated metal pigments and film-forming compositions
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsCraig Matzdorf, William Nickerson
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Abstract
This invention relates to sacrificial-metal pigments coated with an effective amount of at least one metal oxide or a combination of metal oxides such as a mixture of chromium and zirconium oxides, and the process for preparing said coated pigments and combination thereof with film-forming binders for coating metal substrates to inhibit corrosion. The coated sacrificial-metal pigments are electrically active to prevent corrosion of metal substrates that are more cathodic (electropositive) than the metal oxide coated metal pigments.
Claims30
A coated sacrificial-metal pigment having a particle size ranging from about 2 to 100 microns coated with an effective amount of at least one metal oxide selected from the group consisting of chromium oxide, zirconium oxide and mixtures of chromium and zirconium oxides;
- the uncoated metal pigment selected from the group consisting of zinc, magnesium, iron, aluminum, silver, copper and nickel;
- said metal oxide coating derived from an acidic aqueous composition consisting essentially of, in parts by weight, from 0.01 to 22 parts of a trivalent chromate, from 0.01 to 12 parts of hexafluorozirconate, from 0.01 to 12 parts of a fluorocarbon selected from the group consisting of tetrafluoroborate, hexafluorosilicate, and hexaflluorotitanates, from about 0.01 to 12 parts of a divalent zinc compound and from 0.01 to 5.0 parts of a water-soluble corrosion inhibitor.
An electrochemically corrosion-resistant composition for application onto metal substrates consisting essentially of, in parts by weight, from about
- 5 to 80 parts of a film-forming binder selected from the group consisting of an inorganic binder, polyurethanes, polyimides, polyacrylates, polymers derived from diisocyanates, polymers derived from epoxies and the uncured prepolymers of said polymers, from about
- 0.0 to 10 parts of at least one organic corrosion-inhibitor, from about
- 0.0 to 5.0 parts of at least one surfactant, from about
- 0.0 to 5.0 parts of solvent, and from about
- 20 to 80 parts of a coated sacrificial-metal pigment having a particle size ranging from about 2 to 100 microns;
- said sacrificial-metal pigment coated with effective amounts of at least one metal oxide derived from a composition consisting essentially of an acidic aqueous solution comprising from about 0.01 to 22 parts of a trivalent chromium compound, from about 0.01 to 12 parts of hexafluorozirconate, from about 0.01 to 12 parts of at least one fluorocarbon selected from the group consisting of tetrafluoroborates, hexafluorosilicates, and hexafluorotitanates, from about 0.01 to 12 parts of at least one divalent zinc compound, and from about 0.0 to 5 parts by weight of a water-soluble corrosion inhibitor.
An electrochemically corrosion-resistant composition for application onto metal substrates consisting essentially of, in parts by weight, from about
- 5 to 80 parts of an oleaginous composition consisting of an organic lubricant comprising from about
- 0.1 to 10 parts of at least one organic corrosion inhibitor, from about
- 0.1 to 5.0 parts of at least one surfactant, from about
- 1.0 to 5.0 parts of organic solvent, and from about
- 20 to 80 parts by weight of a coated sacrificial-metal pigment having a particle size ranging from about 2 to 100 microns;
- said metal pigment coated with an effective amount of at least one metal oxide derived from an acidic aqueous solution having a ph of about 2.5-5.5 selected from the group consisting of from about 0.01 to 22 parts of a trivalent chromium compound, from about 0.01 to 12 parts of hexafluorozirconate and mixtures thereof, from about 0.01 to 12 parts of at least one fluorocarbon selected from the group consisting of tetrafluoroborates, hexafluorosilicates, and hexafluorotitanates, from about 0.01 to 12 parts of at least one divalent zinc compound, and from about 0.01 to 5 parts by weight of a water soluble corrosion inhibitor.
Dependencies are inferred from the claim text.