US4288299A — Enhanced hydrothermal sealing of anodized aluminum

Claim 1

Independent Claim 188 words

In a method for producing hydrothermally sealed anodized aluminum including initially establishing an anodic oxide coating on a substrate of aluminum or aluminum base alloy; and, subsequently hydrothermally sealing the coating by subjecting the established anodic oxide coating on the substrate to hydrothermal sealing conditions in the presence of an amount of smut-inhibiting agent effective in inhibiting formation of smut incident to hydrothermal sealing, said smut-inhibiting agent being an agent for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating, the improvement which comprises: promoting the hydrothermal sealing of the anodized aluminum by pretreating the established anodic oxide coating prior to hydrothermal sealing, with a basic aqueous medium at a pH in the range of about 7 to about 11 and a temperature of from about 20° C. to about 80° C. for up to about 30 minutes, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating during the subsequent hydrothermal sealing step, but below those required to effect substantial sealing of the coating.

Claim 2

Dependent Claim 188 words

In a method for producing hydrothermally sealed anodized aluminum including initially establishing an anodic oxide coating on a substrate of aluminum or aluminum base alloy; and, subsequently hydrothermally sealing the coating by subjecting the established anodic oxide coating on the substrate to hydrothermal sealing conditions in the presence of an amount of smut-inhibiting agent effective in inhibiting formation of smut incident to hydrothermal sealing, said smut-inhibiting agent being an agent for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating, the improvement which comprises: promoting the hydrothermal sealing of the anodized aluminum by pretreating the established anodic oxide coating prior to hydrothermal sealing, with a basic aqueous medium at a pH in the range of about 7 to about 11 and a temperature of from about 20° C. to about 80° C. for up to about 30 minutes, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating during the subsequent hydrothermal sealing step, but below those required to effect substantial sealing of the coating.

Claim 3

Dependent Claim 31 words

The method of claim 1 wherein said basic aqueous medium is rendered basic by addition of material selected from the group consisting of triethanolomine, ethanolomine, hexamine, sodium borate and sodium carbonate.

Claim 4

Dependent Claim 28 words

The method of claim 2 wherein said material is triethanolamine and the pH of said aqueous medium is in the range of from about 8 to about 10.

Claim 5

Dependent Claim 21 words

The method of claim 1, wherein said temperature is in the range of from about 40° C. to about 50° C.

Claim 6

Dependent Claim 30 words

The method of claim 1, wherein the anodic oxide coating is brought into intimate contact with said aqueous medium for a time of from about 1 to about 15 minutes.

Claim 7

Dependent Claim 156 words

A process for producing a sealed anodic oxide coating on an aluminum substrate comprising: establishing an anodic oxide coating on said substrate; pretreating the anodic oxide coating by subjecting said anodic oxide coating to a mildly basic aqueous medium at a pH in the range of about 7 to about 11 and a temperature of from about 20° C. to about 80° C. for up to about 30 minutes, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating when the coating is subjected to a subsequent hydrothermal sealing step, but below those required to effect substantial sealing; and hydrothermally sealing said pretreated coating in the presence of sufficient anti-smut additive to produce a substantially smut-free surface, said anti-smut additive being an additive for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating.

Claim 8

Dependent Claim 156 words

A process for producing a sealed anodic oxide coating on an aluminum substrate comprising: establishing an anodic oxide coating on said substrate; pretreating the anodic oxide coating by subjecting said anodic oxide coating to a mildly basic aqueous medium at a pH in the range of about 7 to about 11 and a temperature of from about 20° C. to about 80° C. for up to about 30 minutes, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating when the coating is subjected to a subsequent hydrothermal sealing step, but below those required to effect substantial sealing; and hydrothermally sealing said pretreated coating in the presence of sufficient anti-smut additive to produce a substantially smut-free surface, said anti-smut additive being an additive for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating.

Claim 9

Dependent Claim 20 words

The process of claim 6 including the step of electrocoloring said established anodic oxide coating prior to pretreating said coating.

Claim 10

Dependent Claim 49 words

The process of claim 7 wherein said electrocoloring step comprises immersing the anodized aluminum substrate in an acidic bath of a metal salt and depositing in the pores of the anodic oxide coating inorganic particles by the passage of electric current between said anodic oxide coating and a counterelectrode.

Claim 11

Dependent Claim 37 words

The process of claim 8 wherein the electric current used in the electrocoloring step comprises alternating current and the metal salts employed in said process are selected from a group consisting of nickel, cobalt, tin and copper.

Claim 12

Dependent Claim 154 words

A process for enhanced, hydrothermal sealing of anodic oxide coatings established on an aluminum substrate, comprising the steps of: contacting said coating with a basic aqueous media having a pH of from about 7 to about 11, at temperatures from about ambient to about 80° C. and times up to about 30 minutes to pretreat said coating, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating when the coating is subjected to a subsequent hydrothermal sealing step, but below those required to effect substantial sealing of the coating; and hydrothermally sealing said coating in an aqueous sealing bath containing an anti-smut additive in an amount effective to eliminate substantial formation of smut during sealing, said anti-smut additive being an additive for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating.

Claim 13

Dependent Claim 154 words

A process for enhanced, hydrothermal sealing of anodic oxide coatings established on an aluminum substrate, comprising the steps of: contacting said coating with a basic aqueous media having a pH of from about 7 to about 11, at temperatures from about ambient to about 80° C. and times up to about 30 minutes to pretreat said coating, the combination of said conditions being effective to enhance and promote sealing of said anodic oxide coating when the coating is subjected to a subsequent hydrothermal sealing step, but below those required to effect substantial sealing of the coating; and hydrothermally sealing said coating in an aqueous sealing bath containing an anti-smut additive in an amount effective to eliminate substantial formation of smut during sealing, said anti-smut additive being an additive for suppressing formation of crystalline boehmite particles on the surface of the anodic coating while permitting hydration to take place in the pores of the coating.

Claim 14

Dependent Claim 30 words

The process of claim 10 wherein said media is a solution of water and a substance selected from the group consisting of triethanolamine, ethanolamine, hexamine, sodium borate and sodium carbonate.

Claim 15

Dependent Claim 23 words

The process of claim 11 wherein said substance is triethanolamine, and the pH of said solution is from about 8 to about 10.

Claim 16

Dependent Claim 24 words

The process of claim 12 wherein said coating is contacted with said media for a time of from about 1 to about 15 minutes.

Claim 17

Dependent Claim 24 words

The process of claim 10 wherein said contacting is accomplished at a temperature in the range from about 40° C. to about 50° C.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-09-07	1985-03-09	1985-09-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-09-07	1989-03-09	1989-09-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-09-07	1993-03-09	1993-09-08	$7700.00	Window Closed / Lapsed

Enhanced hydrothermal sealing of anodized aluminum

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