TWO-STEP SEALING OF ANODIZED ALUMINUM COATINGS
A method includes providing a workpiece with at least one surface having an anodized aluminum coating and a trivalent chromium sealant. The at least one surface of the workpiece is submerged in a post-treatment sealant solution for 0.5 to 20 minutes. The sealant composition consists essentially of a corrosion inhibitor, an organic complexing agent, and an oxidant.
1 . A sealant composition consisting essentially of:
a corrosion inhibitor;
an organic complexing agent;
an oxidant; and
water.
2 . The composition of claim 1 , wherein the corrosion inhibitor is selected from a group consisting of: a molybdate compound, a silicate compound, a vanadate compound, a Rare earth salt, a phosphate or orthophosphate compound, a phosphate or orthophosphate silicate compound, a phosphate or orthophosphate silicate hydrate compound, a phosphate or orthophosphate silicate hydrate compound that includes at least one of zinc, calcium, strontium, and aluminum cations, and combinations thereof.
3 . The composition of claim 2 , wherein the organic complexing agent is selected from a group consisting of: a poly-amine compound, a polyol compound, a poly-thiol compound, and combinations thereof.
4 . The composition of claim 3 , wherein the organic complexing agent is selected from a group consisting of: a phytate, an EDTA, a thiourea, a benzotriazole, nitrilotriacetic acid, citric acid, a polycarboxylic acid, and combinations thereof.
5 . The composition of claim 3 , wherein the oxidant is selected from a group consisting of: a permanganate, a peroxide, a persulfate, a percarbonate, a perborate, and combinations thereof.
6 . The composition of claim 1 , wherein a concentration of at least one of the corrosion inhibitor, the organic complexing agent, and the oxidant is in a range of 1-50 mM.
7 . The composition of claim 1 , wherein a pH of the composition is between 3 and 9.
8 . The composition of claim 7 , wherein the pH of the composition is between 4 and 6.
9 . A method comprising:
providing a workpiece with at least one surface having an anodized aluminum coating and a trivalent chromium sealant;
submerging the at least one surface of the workpiece in a post-treatment sealing solution for 0.5 to 20 minutes, the sealing solution comprising:
a corrosion inhibitor;
an organic complexing agent;
an oxidant; and
water.
10 . The method of claim 9 , wherein the corrosion inhibitor is selected from a group consisting of: a molybdate compound, a silicate compound, a vanadate compound, a rare earth salt, a phosphate or orthophosphate compound, a phosphate or orthophosphate silicate compound, a phosphate or orthophosphate silicate hydrate compound, a phosphate or orthophosphate silicate hydrate compound that includes at least one of zinc, calcium, strontium, and aluminum cations, and combinations thereof.
11 . The method of claim 10 , wherein the organic complexing agent is selected from a group consisting of: a poly-amine compound, a polyol compound, a poly-thiol compound, and combinations thereof.
12 . The method of claim 11 , wherein the organic complexing agent is selected from a group consisting of: a phytate, an EDTA, a thiourea, a benzotriazole, a nitrilotriacetic acid, a citric acid, a polycarboxylic acid, and combinations thereof.
13 . The method of claim 11 , wherein the oxidant is selected from a group consisting of: a permanganate, a peroxide, a persulfate, a percarbonate, a perborate, and combinations thereof.
14 . The method of claim 9 , further comprising:
maintaining a concentration of one or more of the components in a range of 1 to 50 mM.
15 . The method of claim 9 , further comprising:
maintaining a solution pH in a range between 3 and 9.
16 . The method of claim 9 , further comprising:
maintaining a process temperature in a range of 20° C. to 80° C.
17 . The method of claim 9 , wherein the sealant composition further comprises a surfactant.
18 . A sealant composition consisting essentially of:
a corrosion inhibitor;
an organic complexing agent;
an oxidant;
a surfactant; and
water.
19 . The composition of claim 18 , wherein:
the corrosion inhibitor is selected from a group consisting of: a molybdate compound, a silicate compound, a vanadate compound, a rare earth salt, a phosphate or orthophosphate compound, a phosphate or orthophosphate silicate compound, a phosphate or orthophosphate silicate hydrate compound, a phosphate or orthophosphate silicate hydrate compound that includes at least one of zinc, calcium, strontium, and aluminum cations, and combinations thereof;
the organic complexing agent is selected from a group consisting of: a poly-amine compound, a polyol compound, a poly-thiol compound, and combinations thereof; and
the oxidant is selected from a group consisting of: a permanganate, a peroxide, a persulfate, a percarbonate, a perborate, and combinations thereof.
20 . The composition of claim 9 , wherein:
a concentration of at least one of the corrosion inhibitor, the organic complexing agent, and the oxidant is in a range of 1 to 50 mM; and
a solution pH is in a range between 3 and 9.