Fastener coating and process

Abstract

Corrosion resistant fasteners and similar articles are compositely coated in which an epoxy base coating is applied on an inner metallic core and a top coating is applied on the epoxy coating. The epoxy base coat is preferably applied on the metallic core by cathodic electrodeposition. The composition of the top coating can comprise sulfonates such as petroleum sulfonates and sulfurized hydrocarbon fatty acid and ester. Hydrocarbon fatty acid ester in the top coat can be derived from polymer of ethylene or propylene or natural oil. Particularly preferred top coat formulations additionally include a salt of sulfamic acid or a derivative and/or salts of barium such as barium carbonate and barium sulfate. The composite coatings provide improvement in corrosion resistance of the fasteners.

Dependencies are inferred from the claim text.