Phosphate coating which can be substantially free of hexavalent chromium and methods of making the same
Disclosed is a phosphate coating, comprising: a phosphate portion, wherein the phosphate portion comprises pores, wherein the pores are at least partially filled with a corrosion inhibition sealant, wherein the corrosion inhibition sealant comprises: a base, wherein the base comprises a matrix and a metal within the matrix, wherein the metal within the matrix comprises aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a combination thereof and an inhibitor mixed within the base, wherein the inhibitor comprises zinc molybdate, magnesium metasilicate, trivalent chromium, tungstenate, a metal phosphate silicate, or a combination thereof.
1. A phosphate coating, comprising:
a phosphate portion, wherein the phosphate portion comprises pores,
wherein the pores are at least partially filled with a corrosion inhibition sealant, wherein the corrosion inhibition sealant comprises:
a base, wherein the base comprises a matrix and a metal within the matrix, wherein the metal within the matrix comprises aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a combination thereof; and
an inhibitor mixed within the base,
wherein the phosphate coating has less than or equal to about 1.0% hexavalent chromium by weight based on a total weight of the phosphate coating,
wherein i) the inhibitor comprises trivalent chromium, tungstenate, or a combination thereof, ii) the matrix comprises polyurethane, or iii) a combination thereof.
2. The phosphate coating of claim 1 , wherein the phosphate portion comprises iron phosphate, manganese phosphate, zinc phosphate, or a combination thereof.
3. The phosphate coating of claim 1 , wherein the corrosion inhibition sealant comprises:
about 70% to about 95% base by volume; and
about 5% to about 30% inhibitor by volume.
4. The phosphate coating of claim 1 , wherein the corrosion inhibition sealant comprises less than or equal to about 10% inhibitor by volume.
5. The phosphate coating of claim 1 , wherein the inhibitor is a powder.
6. The phosphate coating of claim 1 , wherein, in addition to the corrosion inhibition sealant, the pores of the phosphate portion are also at least partially filled with paint, oil, wax, lubricant, film, or a combination thereof.
7. A substrate coated with the phosphate coating of claim 1 , wherein the substrate comprises ferrous metal, an electroplated coating, or a combination thereof.
8. The substrate of claim 7 , wherein the substrate comprises an electroplated coating, wherein the electroplated coating comprises cadmium, titanium-cadmium, zinc, nickel, zinc-nickel, zinc-iron, zinc-cobalt, selenium-zinc, tin-zinc, or a combination thereof.
9. The substrate of claim 7 , wherein the substrate is an aircraft component, wherein the aircraft component is a propeller blade, a propeller shank, a propeller hub, a propeller barrel, a propeller tulip, a landing gear component, an engine gear, an engine disc, a shaft, a strut, or a counterweight.
10. A method of forming a phosphate coating, comprising:
applying a solution of phosphoric acid and phosphate salt to a surface of a substrate, wherein the solution chemically reacts with the surface of the substrate and forms a phosphate portion, wherein the phosphate portion comprises pores; and
applying a corrosion inhibition sealant to the phosphate portion, wherein the pores of the phosphate portion are at least partially filled with the corrosion inhibition sealant, wherein the corrosion inhibition sealant comprises:
a base, wherein the base comprises a matrix and a metal within the matrix, wherein the metal within the matrix comprises aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a combination thereof; and
an inhibitor mixed within the base,
wherein the phosphate coating has less than or equal to about 1.0% hexavalent chromium by weight based on a total weight of the phosphate coating,
wherein i) the inhibitor comprises trivalent chromium, tungstenate, or a combination thereof, ii) the matrix comprises polyurethane, or iii) a combination thereof.
11. The method of claim 10 , wherein applying the solution comprises spraying, immersion, or a combination thereof.
12. The method of claim 10 , wherein the phosphate portion comprises iron phosphate, manganese phosphate, zinc phosphate, or a combination thereof.
13. The method of claim 10 , wherein, in addition to the corrosion inhibition sealant, the pores of the phosphate portion are also at least partially filled with paint, oil, wax, lubricant, film, or a combination thereof.
14. The method of claim 10 , wherein the substrate comprises ferrous metal, an electroplated coating, or a combination thereof.