Coating composition and method
AssigneeHooker Chemicals & Plastics Corporation
InventorGary A. Reghi
Life of this patent
Estimating the term…
Abstract
An aqueous acidic composition provides improved corrosion resistance to a metal, e.g., ferrous, zinc or aluminum surface upon contact. The composition contains dissolved hafnium and/or zirconium, fluoride, preferably a vegetable tannin compound, and optionally phosphate ions.
Claims81
An acidic aqueous chromium-free composition of pH value less than 5 containing in dissolved form hafnium, fluoride and a vegetable tannin in amounts, at least 1 ppm of each, sufficient, when contacted with a metal surface, to impart corrosion resistance to the metal surface.
A chromium-free process for forming a corrosion resistant paint receptive coating on a metal surface comprising contacting the surface with an aqueous acidic composition of pH value less than 5 containing at least 1 ppm of both dissolved hafnium and fluoride for a time and at a temperature sufficient to produce a coating thereon.
An acidic aqueous chromium-free composition of pH value less than 5 containing in dissolved form phosphate ions in an amount of about 10 up to about 200 ppm and zirconium, fluroide and a vegetable tannin in amounts, at least 1 ppm of each, sufficient, when contacted with a metal surface, to impart corrosion resistance to the metal surface.
An acidic aqueous chromium-free composition of pH value of about 3 to about 4.5 containing in dissolved form zirconium, fluoride and a vegetable tannin amounts, at least 1 ppm of each, sufficient, when contacted with a metal surface, to impart corrosion resistance to the metal surface.
Dependencies are inferred from the claim text.