Dry-in-place corrosion-resistant coating for zinc or zinc-alloy coated substrates

Abstract

A process for making a corrosion-resistant metal component. The process having the steps of: combining water, at least one zinc phosphate forming compound and at least one chromium forming compound, being chromium (III) or chromium (IV) compounds, to form a first solution; separately combining at least one silicate compound with water to form a second solution; combining the first solution with the second solution such as to form a mixed aqueous solution; optionally combining the mixed aqueous solution with at least one acrylic resin to form a coating mixture; and, applying the coating mixture to the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface, and the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2 (12.20 g/m 2 ).

1 . A process for making a corrosion-resistant metal component comprising the steps of:
 combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution;   separately combining at least one silicate compound with water to form a second solution;   combining the first solution with the second solution such as to form a mixed aqueous solution;   combining the mixed aqueous solution with at least one acrylic resin to form a coating mixture; and   applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface, and the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2  (12.20 g/m 2 ).   
     
     
         2 . A process for making a corrosion-resistant metal component as claimed in  claim 1 , further comprising the step of heating the coated metal substrate to further the reaction between the applied coating mixture and the surface of the metal substrate. 
     
     
         3 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the zinc or zinc-alloy surface is selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combinations thereof. 
     
     
         4 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the first solution comprises:
 not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; 
 not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and 
 balance water. 
 
     
     
         5 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the first solution comprises:
 not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; 
 not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and 
 balance water. 
 
     
     
         6 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the second solution comprises:
 not less than 10 and not more than 50 percent by weight of at least one silicate compound; and 
 balance water. 
 
     
     
         7 . A process for making a corrosion-resistant metal component as claimed in  claim 1 , wherein the coating mixture comprises:
 not less than 20 and not more than 95 percent by weight of the first solution;   not less than 5 and not more than 12 percent by weight of the second solution;   not less than 5 and not more than 30 percent by weight of the at least one acrylic resin; and   balance water.   
     
     
         8 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the at least one acrylic resin has a pH value of no greater than 3.5. 
     
     
         9 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the at least the coating mixture has a pH value of no greater than 2.5. 
     
     
         10 . A process for making a corrosion-resistant metal component as claimed in  1  wherein the at least one silicate compound comprises a potassium silicate compound. 
     
     
         11 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the at least one chromium forming compound comprises a trivalent chromium forming compound. 
     
     
         12 . A process for making a corrosion-resistant metal component as claimed in  claim 11  wherein the trivalent chromium forming compound is selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof. 
     
     
         13 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the at least one chromium forming compound comprises a hexavalent chromium forming compound. 
     
     
         14 . A process for making a corrosion-resistant metal component as claimed in  claim 13  wherein the hexavalent chromium forming compound is selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof. 
     
     
         15 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the step of applying the coating mixture comprises rolling the coating mixture onto the metal component surface. 
     
     
         16 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the step of applying the coating mixture comprises spraying the coating mixture onto the metal component surface. 
     
     
         17 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the step of applying the coating mixture comprises submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the coating mixture. 
     
     
         18 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the step of applying the coating mixture solution further comprises filling any voids in the zinc or zinc-alloy surface with the coating mixture solution. 
     
     
         19 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the coating provides electrical conductivity. 
     
     
         20 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the coating is water-repellant. 
     
     
         21 . A process for making a corrosion-resistant metal component as claimed in  claim 1  wherein the coating provides an enhanced surface for a zinc or zinc-alloy coated metal component for adhesion to paints. 
     
     
         22 . A process for making a corrosion-resistant metal component coating as claimed in  claim 1  wherein the coating is self-healing. 
     
     
         23 . A process for making a corrosion-resistant metal component comprising the steps of:
 combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution;   separately combining at least one silicate compound with water to form a second solution;   combining the first solution with the second solution such as to form a coating mixture; and   applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface, and the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2  (12.20 g/m 2 ).   
     
     
         24 . A process for making a corrosion-resistant metal component as claimed in  claim 23 , further comprising the step of heating the coated metal substrate to further the reaction between the applied coating mixture and the surface of the substrate. 
     
     
         25 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the zinc or zinc-alloy surface is selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combinations thereof. 
     
     
         26 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the first solution comprises:
 not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; 
 not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and 
 balance water. 
 
     
     
         27 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the first solution comprises:
 not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound; 
 not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and 
 balance water. 
 
     
     
         28 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the second solution comprises:
 not less than 10 and not more than 50 percent by weight of at least one silicate compound; and 
 balance water. 
 
     
     
         29 . A process for making a corrosion-resistant metal component as claimed in  claim 23 , wherein the coating mixture comprises:
 not less than 20 and not more than 95 percent by weight of the first solution;   not less than 5 and not more than 12 percent by weight of the second solution; and   balance water.   
     
     
         30 . A process for making a corrosion-resistant metal component as claimed in  23  wherein the at least one silicate compound comprises a potassium silicate compound. 
     
     
         31 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the coating mixture has a pH value of no greater than 2.5. 
     
     
         32 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the at least one chromium forming compound comprises a trivalent chromium forming compound. 
     
     
         33 . A process for making a corrosion-resistant metal component as claimed in  claim 32  wherein the trivalent chromium forming compound is selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof. 
     
     
         34 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the at least one chromium forming compound comprises a hexavalent chromium forming compound. 
     
     
         35 . A process for making a corrosion-resistant metal component as claimed in  claim 34  wherein the hexavalent chromium forming compound is selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof. 
     
     
         36 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the step of applying the coating mixture comprises rolling the coating mixture onto the metal component surface. 
     
     
         37 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the step of applying the coating mixture comprises spraying the coating mixture onto the metal component surface. 
     
     
         38 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the step of applying the coating mixture comprises submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the coating mixture. 
     
     
         39 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the step of applying the coating mixture solution further comprises filling any voids in the zinc or zinc-alloy surface with the coating mixture solution. 
     
     
         40 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the coating provides electrical conductivity. 
     
     
         41 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the coating is water-repellant. 
     
     
         42 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the coating provides an enhanced surface for a zinc or zinc-alloy coated metal component for adhesion to paints. 
     
     
         43 . A process for making a corrosion-resistant metal component as claimed in  claim 23  wherein the coating is self-healing. 
     
     
         44 . A process for making a corrosion-resistant metal component coating comprising the steps of:
 combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution;   separately combining at least one silicate compound with water to form a second solution;   combining the first solution with the second solution such as to form a mixed aqueous solution;   combining the mixed aqueous solution with at least one acrylic resin to form a coating mixture; and   applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface, and the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2  (12.20 g/m 2 ).   
     
     
         45 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44 , further comprising the step of heating the coated metal substrate to further the reaction between the applied coating mixture and the surface of the metal substrate. 
     
     
         46 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44 , wherein the zinc or zinc-alloy surface is selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combinations thereof. 
     
     
         47 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44 , wherein the first solution comprises:
 not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound;   not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and   balance water.   
     
     
         48 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44 , wherein the first solution comprises:
 not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound;   not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and   balance water.   
     
     
         49 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the second solution comprises:
 not less than 10 and not more than 50 percent by weight of at least one silicate compound; and 
 balance water. 
 
     
     
         50 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44 , wherein the coating mixture comprises:
 not less than 20 and not more than 95 percent by weight of the first solution;   not less than 5 and not more than 12 percent by weight of the second solution;   not less than 5 and not more than 30 percent by weight of the at least one acrylic resin; and   balance water.   
     
     
         51 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the at least one acrylic resin has a pH value of no greater than 3.5. 
     
     
         52 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the coating mixture has a pH value of no greater than 2.5. 
     
     
         53 . A process for making a corrosion-resistant metal component coating as claimed in  44  wherein the at least one silicate compound comprises a potassium silicate compound. 
     
     
         54 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the at least one chromium forming compound comprises a trivalent chromium forming compound. 
     
     
         55 . A process for making a corrosion-resistant metal component coating as claimed in  claim 54  wherein the trivalent chromium forming compound is selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof. 
     
     
         56 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the at least one chromium forming compound comprises a hexavalent chromium forming compound. 
     
     
         57 . A process for making a corrosion-resistant metal component coating as claimed in  claim 56  wherein the hexavalent chromium forming compound is selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof. 
     
     
         58 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the step of applying the coating mixture comprises rolling the coating mixture onto the metal component surface. 
     
     
         59 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the step of applying the coating mixture comprises spraying the coating mixture onto the metal component surface. 
     
     
         60 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the step of applying the coating mixture comprises submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the coating mixture. 
     
     
         61 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the step of applying the coating mixture solution further comprises filling any voids in the zinc or zinc-alloy surface with the coating mixture solution. 
     
     
         62 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the corrosion-resistant metal component coating provides electrical conductivity. 
     
     
         63 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the corrosion-resistant metal component coating is water-repellant. 
     
     
         64 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the corrosion-resistant metal component coating provides an enhanced surface for a zinc or zinc-alloy coated metal component for adhesion to paints. 
     
     
         65 . A process for making a corrosion-resistant metal component coating as claimed in  claim 44  wherein the corrosion-resistant metal component coating is self-healing. 
     
     
         66 . A process for making a corrosion-resistant metal component coating comprising the steps of:
 combining water, at least one zinc phosphate forming compound and at least one chromium forming compound to form a first solution;   separately combining at least one silicate compound with water to form a second solution;   combining the first solution with the second solution such as to form a coating mixture; and   applying the coating mixture to a metal substrate having a zinc or zinc-alloy surface to form a coating on the metal substrate that reacts with the zinc or zinc-alloy surface of the metal substrate forming a covalent bond with the zinc or zinc-alloy surface, and the coating providing chemical resistance for at least 150 hours in accordance with ASTM B117 standards where the zinc or zinc-alloy coating of the metal substrate has a weight of 0.04 oz/ft 2  (12.20 g/m 2 ).   
     
     
         67 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66 , further comprising the step of heating the coated metal substrate to further the reaction between the applied coating mixture and the surface of the metal substrate. 
     
     
         68 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66 , wherein the zinc or zinc-alloy surface is selected from the group consisting of zinc, zinc alloy, zinc-aluminum alloy, zinc-iron alloy, zinc-aluminum-magnesium alloy and combinations thereof. 
     
     
         69 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66 , wherein the first solution comprises:
 not less than 4 and not more than 27 percent by weight of the at least one zinc phosphate forming compound;   not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and   balance water.   
     
     
         70 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66 , wherein the first solution comprises:
 not less than 5 and not more than 27 percent by weight of the at least one zinc phosphate forming compound;   not less than 5 and not more than 27 percent by weight of the at least one chromium forming compound; and   balance water.   
     
     
         71 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the second solution comprises:
 not less than 10 and not more than 50 percent by weight of at least one silicate compound; and 
 balance water. 
 
     
     
         72 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66 , wherein the coating mixture comprises:
 not less than 20 and not more than 95 percent by weight of the first solution;   not less than 5 and not more than 12 percent by weight of the second solution; and   balance water.   
     
     
         73 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the coating mixture has a pH value of no greater than 2.5. 
     
     
         74 . A process for making a corrosion-resistant metal component coating as claimed in  66  wherein the at least one silicate compound comprises a potassium silicate compound. 
     
     
         75 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the at least one chromium forming compound comprises a trivalent chromium forming compound. 
     
     
         76 . A process for making a corrosion-resistant metal component coating as claimed in  claim 75  wherein the trivalent chromium forming compound is selected from the group consisting of chromium chloride hydrate, chromium (III) potassium sulfate, chromium hydroxide, chromium (III) fluoride, chromium (III) sulfate, chromium (III) sulfide, chromium (III) oxide, chromium (III) 2-ethylhexanoate, chromium (III) nitride, chromium tricarbonyl and mixtures thereof. 
     
     
         77 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the at least one chromium forming compound comprises a hexavalent chromium forming compound. 
     
     
         78 . A process for making a corrosion-resistant metal component coating as claimed in  claim 77  wherein the hexavalent chromium forming compound is selected from the group consisting of chromium (VI) halides, hexafluoride, chromyl chloride, sodium chromate, chromium (VI) peroxide, sodium chromate, chromium (VI) oxide, dichromate, potassium chromate, calcium chromate, barium chromate, chromium (VI) oxide peroxide, and mixtures thereof. 
     
     
         79 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the step of applying the coating mixture comprises rolling the coating mixture onto the metal component surface. 
     
     
         80 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the step of applying the coating mixture comprises spraying the coating mixture onto the metal component surface. 
     
     
         81 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the step of applying the coating mixture comprises submersing at least a portion of the metal substrate with a zinc or zinc-alloy surface into a bath of the coating mixture. 
     
     
         82 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the step of applying the coating mixture solution further comprises filling any voids in the zinc or zinc-alloy surface with the coating mixture solution. 
     
     
         83 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the step of applying the coating mixture solution further comprises filling any voids in the zinc or zinc-alloy surface with the coating mixture solution. 
     
     
         84 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the corrosion-resistant metal component coating provides electrical conductivity. 
     
     
         85 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the corrosion-resistant metal component coating is water-repellant. 
     
     
         86 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the corrosion-resistant metal component coating provides an enhanced surface for a zinc or zinc-alloy coated metal component for adhesion to paints. 
     
     
         87 . A process for making a corrosion-resistant metal component coating as claimed in  claim 66  wherein the corrosion-resistant metal component coating is self-healing.