Hexavalent chromium-free phosphate-bonded coatings
AssigneeSermatech International, Inc.
InventorsRonald E. Myers, Mark F. Mosser, Kevin B. Eddinger, John E. Hughes
Life of this patent
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Abstract
A heat curable bonding composition of the present invention comprises an aqueous solution containing phosphate ion (PO4−3) and chromium(III) ion (Cr+3, or trivalent chromium) and is substantially free of hexavalent chromium ions. The bonding composition may further contain at least one secondary cationic species. The bonding composition has a pH in the range of about 1 to about 3.5.
Claims30
A heat curable coating composition comprising metallic aluminum particles dispersed in a heat curable bonding composition comprising:
- (a) phosphate ions and chromium(III) ions;
- and
- (b) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A coated article comprising a solid substrate having deposited thereon at least one layer of a coating formed by the steps of:
- (a) applying a heat curable coating composition comprising metallic aluminum particles dispersed in a bonding composition comprising
- (1) phosphate ions and chromium(III) ions;
- and
- (2) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A method of forming a coating on a solid substrate comprising the steps of:
- (a) applying to the substrate a heat curable coating composition comprising metallic aluminum particles dispersed in a heat curable bonding composition comprising
- (1) phosphate ions and chromium(III) ions;
- and
- (2) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A heat curable bonding composition for a heat curable coating for coating a substrate, the heat curable bonding composition comprising:
- (a) phosphate ions and chromium(III) ions;
- and
- (b) water;
- and
- (c) at least one secondary cationic species
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A heat curable bonding composition for a heat curable coating for coating a substrate, the heat curable bonding composition comprising:
- (a) phosphate ions and chromium(III) ions;
- and
- (b) water;
- and
- wherein the composition has a pH in the range from about 1.0 to about 3.5, is substantially free of chromate, and has a nonvolatile content in the range from about 15 wt % to about 35 wt %.
A heat curable topcoat composition comprising:
- (a) phosphate ions and chromium(III) ions;
- (b) water;
- (c) a secondary cationic species;
- and
- (d) at least one additive selected from the group consisting of wetting agents, film forming agents, corrosion inhibitors, dry lubricants, refractory compounds, chromatic pigments, and combinations thereof;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A coated article comprising a solid substrate having deposited thereon at least one layer of a coating formed by the steps of:
- (a) applying to the substrate a heat curable coating composition comprising:
- (1) phosphate ions and chromium(III) ions;
- (2) water;
- and
- (3) a secondary cationic species, wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate;
- and
- (b) heat curing the applied coating composition to produce said coating.
A coated article comprising a solid substrate having deposited thereon at least one layer of a coating formed by the steps of applying to the substrate a heat curable coating composition comprising:
- (1) phosphate ions and chromium(III) ions;
- and
- (2) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5, is substantially free of chromate;
- and, has a nonvolatile content in the range from about 15 wt % to about 35 wt %.
A method of forming a coating on a solid substrate comprising the steps of:
- (a) applying to the substrate a heat curable coating composition comprising:
- (1) phosphate ions and chromium(i) ions;
- (2) water;
- and
- (3) a secondary cationic species, wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate;
- and
- (b) heat curing the applied coating composition to produce said coating.
A heat curable bonding composition for a heat curable coating for coating a substrate, the heat curable bonding composition comprising:
- (a) phosphate ions and chromium(III) ions;
- and
- (b) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5, is substantially free of chromate, and has a molar ratio of phosphate ions to chromium(III) ions of at least about 3.5.
A heat curable bonding composition for a heat curable coating for coating a substrate, the heat curable bonding composition consisting essentially of:
- (a) phosphate ions and chromium(ill) ions;
- and
- (b) water;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
A heat curable topcoat composition consisting essentially of:
- (a) phosphate ions and chromium(III) ions;
- and
- (b) water;
- (c) at least one additive selected from the group consisting of wetting agents, film-forming agents, corrosion inhibitors, dry lubricants, refractory compounds, chromatic pigments, and combinations thereof;
- wherein the composition has a pH in the range from about 1.0 to about 3.5 and is substantially free of chromate.
Dependencies are inferred from the claim text.