US4659629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of a protective outer layer on magnesium alloys containing aluminum
Assignee: Dow Chemical Co
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Filing: 1985-11-25
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Granted: 1987-04-21
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Expires: 2005-11-25
Abstract
Abstract A process is disclosed for the protection of magnesium based alloys containing aluminum by treatment with eutectic mixtures of fused salts to provide a corrosion resistant outer layer on the magnesium based alloy. A suitable fused salt mixture comprises urea and at least one of ammonium nitrate or ammonium nitrite. A magnesium based alloy is also disclosed comprising magnesium and aluminum having a corrosion resistant outer layer comprising magnesium oxide and aluminum oxide; the proportion of aluminum present in the outer layer being enriched in proportion to the amount present in the magnesium based alloy.
Inventors
- 👤 Charles D. Gartner
- 👤 Patrick L. Hagans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 00:34
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/70
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
77 words
A magnesium based alloy containing a minor amount of aluminum having an outer layer comprising aluminum oxide and magnesium oxide prepared by exposing said alloy to electroless coating conditions in the presence of a molten fused salt eutectic mixture comprising an organic component and at least one of a nitrate or nitrite, wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount of aluminum present in said magnesium based alloy.
Claim 2
Dependent Claim
77 words
A magnesium based alloy containing a minor amount of aluminum having an outer layer comprising aluminum oxide and magnesium oxide prepared by exposing said alloy to electroless coating conditions in the presence of a molten fused salt eutectic mixture comprising an organic component and at least one of a nitrate or nitrite, wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount of aluminum present in said magnesium based alloy.
Claim 3
Dependent Claim
27 words
The composition of claim 1 wherein said organic component of said eutectic mixture comprises urea, said nitrate salt is ammonium nitrate, and said eutectic mixture contains water.
Claim 4
Dependent Claim
15 words
The composition of claim 2 wherein said eutectic mixture contains 40.4 mole percent ammonium nitrate.
Claim 5
Dependent Claim
22 words
The composition of claim 3 wherein the proportion of water in said eutectic mixture is about 0.01 to about 5 weight percent.
Claim 6
Dependent Claim
21 words
The composition of claim 4 wherein the proportion of aluminum in said alloy is about 5% to about 20% by weight.
Claim 7
Dependent Claim
14 words
The composition of claim 5 wherein said alloy contains 9% aluminum and 1% zinc.
Claim 8
Dependent Claim
19 words
The composition of claim 5 wherein the proportion of aluminum present in said outer layer is a predominating proportion.
Claim 9
Dependent Claim
78 words
A magnesium based alloy containing a minor amount of aluminum having an outer layer comprising aluminum oxide and magnesium oxide prepared by exposing said alloy to electrolytic coating conditions in the presence of a molten fused salt eutectic mixture comprising an organic component and at least one of a nitrate or nitrite and wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount of aluminum present in said magnesium based alloy.
Claim 10
Dependent Claim
78 words
A magnesium based alloy containing a minor amount of aluminum having an outer layer comprising aluminum oxide and magnesium oxide prepared by exposing said alloy to electrolytic coating conditions in the presence of a molten fused salt eutectic mixture comprising an organic component and at least one of a nitrate or nitrite and wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount of aluminum present in said magnesium based alloy.
Claim 11
Dependent Claim
27 words
The composition of claim 8 wherein said organic component of said eutectic mixture comprises urea, said nitrate salt is ammonium nitrate, and said eutectic mixture contains water.
Claim 12
Dependent Claim
15 words
The composition of claim 9 wherein said eutectic mixture contains 40.4 mol percent ammonium nitrate.
Claim 13
Dependent Claim
22 words
The composition of claim 10 wherein the proportion of water in said eutectic mixture is about 0.01 to about 5 weight percent.
Claim 14
Dependent Claim
21 words
The composition of claim 11 wherein the proportion of aluminum in said alloy is about 5% to about 20% by weight.
Claim 15
Dependent Claim
14 words
The composition of claim 12 wherein said alloy contains 9% aluminum and 1% zinc.
Claim 16
Dependent Claim
19 words
The composition of claim 12 wherein the proportion of aluminum present in said outer layer is a predominating proportion.
Claim 17
Dependent Claim
129 words
A process for producing a corrosion resistant outer layer on a magnesium based alloy containing a minor amount of aluminum, said process comprising: (A) exposing said alloy to electroless coating conditions in the presence of an eutectic mixture at a temperature above the melting point of said eutectic mixture, or (B) exposing said alloy to electrolytic coating conditions in the presence of an eutectic mixture and at a temperature above the melting point of said eutectic mixture, and (C) forming an outer layer comprising aluminum oxide and magnesium oxide wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount present in said alloy , and wherein said eutectic mixture comprises an organic component and at least one of a nitrate or nitrite.
Claim 18
Dependent Claim
129 words
A process for producing a corrosion resistant outer layer on a magnesium based alloy containing a minor amount of aluminum, said process comprising: (A) exposing said alloy to electroless coating conditions in the presence of an eutectic mixture at a temperature above the melting point of said eutectic mixture, or (B) exposing said alloy to electrolytic coating conditions in the presence of an eutectic mixture and at a temperature above the melting point of said eutectic mixture, and (C) forming an outer layer comprising aluminum oxide and magnesium oxide wherein the proportion of aluminum present in said outer layer is enriched in proportion to the amount present in said alloy , and wherein said eutectic mixture comprises an organic component and at least one of a nitrate or nitrite.
Claim 19
Dependent Claim
24 words
The process of claim 15 wherein said eutectic mixture comprises water, urea, and at least one of an ammonium nitrate or nitrite fused salt.
Claim 20
Dependent Claim
51 words
The process of claim 16 wherein said eutectic mixture contains 40.4 mol percent by weight of ammonium nitrate and said outer layer is formed on said alloy at a temperature of about 50° centigrade or 85° centigrade wherein the proportion of aluminum present in said outer layer is a predominating proportion.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |