CHROMIUM-FREE PASSIVATION OF VAPOR DEPOSITED ALUMINUM SURFACES
A process for passivating a vapor-deposited aluminum layer on a substrate, including providing a substrate comprising vapor deposited aluminum on a surface thereof; treating the surface of the substrate with an aqueous substantially chromium-free composition comprising a hexafluorozirconate; and rinsing the treated surface with water. A process for passivating a vapor-deposited aluminum layer on a substrate, including vapor depositing a layer of aluminum on a substrate; treating the substrate with the vapor deposited aluminum with an aqueous substantially chromium-free composition comprising a hexafluorozirconate; and rinsing the treated substrate with water.
1 . A process for passivating a vapor-deposited aluminum layer on a substrate, comprising:
providing a substrate comprising vapor deposited aluminum on a surface thereof;
treating the surface of the substrate with an aqueous substantially chromium-free composition comprising a hexafluorozirconate; and
rinsing the treated surface with water.
2 . The process of claim 1 wherein the chromium-free composition comprising a hexafluorozirconate further comprises a magnesium salt, a nickel salt, a zinc salt or a combination of any two or more of a magnesium salt, a nickel salt and a zinc salt.
3 . The process of claim 1 wherein the vapor deposited aluminum is applied to the surface by decomposition of a metal-containing precursor having a decomposition temperature in a surrounding atmosphere, in which the substrate is maintained at a temperature greater than the decomposition temperature of the precursor while the surrounding atmosphere is maintained at a temperature lower than the decomposition temperature of the precursor.
4 . The process of claim 1 wherein the vapor deposited aluminum is applied to the surface by one or a combination of two or more of chemical vapor deposition, ion vapor deposition and physical vapor deposition.
5 . The process of claim 1 wherein the substrate comprises a ferrous metal on which the aluminum is vapor deposited.
6 . The process of claim 5 wherein the ferrous metal is steel.
7 . The process of claim 1 wherein the aqueous chromium-free composition is free of added zinc ions.
8 . The process of claim 1 wherein the aqueous chromium-free composition is free of added alkali metal ions.
9 . The process of claim 1 further comprising depositing at least one additional layer over the treated layer of aluminum, wherein the additional layer comprises one or more of a metal layer or an organic coating.
10 . The process of claim 1 wherein the hexafluorozirconate is provided as one or a mixture of any two or more of hexafluorozirconic acid, ammonium hexafluorozirconate, a quaternary ammonium hexafluorozirconate, an alkali metal hexafluorozirconate, an alkaline earth metal hexafluorozirconate, or a transition metal hexafluorozirconate.
11 . A process for passivating a vapor-deposited aluminum layer on a substrate, comprising:
vapor depositing a layer of aluminum on a substrate;
treating the substrate with the vapor deposited aluminum with an aqueous substantially chromium-free composition comprising a hexafluorozirconate; and
rinsing the treated substrate with water.
12 . The process of claim 11 wherein the chromium-free composition comprising a hexafluorozirconate further comprises a magnesium salt, a nickel salt, a zinc salt or a combination of any two or more of a magnesium salt, a nickel salt and a zinc salt.
13 . The process of claim 11 wherein the vapor depositing is by decomposition of a metal-containing precursor having a decomposition temperature in a surrounding atmosphere, in which the substrate is maintained at a temperature greater than the decomposition temperature of the precursor while the surrounding atmosphere is maintained at a temperature lower than the decomposition temperature of the precursor.
14 . The process of claim 11 wherein the vapor depositing is by one or a combination of two or more of chemical vapor deposition, ion vapor deposition and physical vapor deposition.
15 . The process of claim 11 wherein the substrate comprises a ferrous metal.
16 . The process of claim 15 wherein the ferrous metal is steel.
17 . The process of claim 11 wherein the aqueous chromium-free composition is free of added zinc ions.
18 . The process of claim 11 wherein the aqueous chromium-free composition is free of added alkali metal ions.
19 . The process of claim 11 further comprising depositing at least one additional layer over the treated layer of aluminum, wherein the additional layer comprises one or more of a metal layer or an organic coating.
20 . The process of claim 11 wherein the hexafluorozirconate is provided as one or a mixture of any two or more of hexafluorozirconic acid, ammonium hexafluorozirconate, a quaternary ammonium hexafluorozirconate, an alkali metal hexafluorozirconate, an alkaline earth metal hexafluorozirconate, or a transition metal hexafluorozirconate.