US4022585A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for sealing composites against moisture and articles made thereby
Assignee: General Dynamics Corp
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Filing: 1975-04-21
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Granted: 1977-05-10
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Expires: 1995-04-21
Abstract
Abstract A method for sealing and protecting the surface of advanced composite materials against moisture and other contaminants. Advanced composite materials, which comprise high strength fibers such as graphite or boron fibers in a resin matrix such as epoxy or polyimide resins, suffer a performance loss when subjected to moisture. In high vacuum environments, such as in many outer space applications, resin binder outgassing may cause contamination of the overall device. Significant dimensional changes occur when these composite structures are used in environments with widely varying humidity levels. The disclosed method of preventing such degradation basically comprises the steps of undercoating the surface with a metal coating, fluxing the undercoat, forming a layer of molten metal on the undercoat then solidifying the metal topcoating. A seal coating substantially impervious to water and highly resistant to dimensional changes and corrosion results.
Inventors
- 👤 Samuel Kaye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:40
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1633; C23C18/1646; C23C18/165; C23C18/1653; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/12028; Y10T428/12049
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
66 words
A moisture impervious composite structure comprising: a structure comprising fibers embedded in a synethetic resin matrix; an adherent metallic undercoating covering the surface of said structure; a uniform, non-porous, moisture impervious fusible metal top coat covering the surface of said undercoat, said top coat solidified from a fused state in place over said undercoat; said top coat being substantially free of open paths between its surfaces.
Claim 2
Dependent Claim
66 words
A moisture impervious composite structure comprising: a structure comprising fibers embedded in a synethetic resin matrix; an adherent metallic undercoating covering the surface of said structure; a uniform, non-porous, moisture impervious fusible metal top coat covering the surface of said undercoat, said top coat solidified from a fused state in place over said undercoat; said top coat being substantially free of open paths between its surfaces.
Claim 3
Dependent Claim
12 words
The structure according to claim 1 wherein said fibers comprise graphite fibers.
Claim 4
Dependent Claim
38 words
The structure according to claim 1 wherein said undercoat comprises copper and said top coat comprises a mixture of from about 48 to about 52 weight percent tin and from about 52 to about 48 weight percent indium.
Claim 5
Dependent Claim
35 words
The structure according to claim 3 wherein said undercoat has a thickness of from about 0.00025 to about 0.00035 inch and said top coat has a thickness of from about 0.2 to about 0.6 mil.
Claim 6
Independent Claim
85 words
The method of forming a moisture impervious coating on composite structures which comprises the steps of: providing a composite structure comprising fibers embedded in a synthetic resin matrix; forming a metal undercoating over the structure surface; forming a top coat substantially free of open paths between its surfaces over said undercoat by solidifying a fused metal coating from an entirely fused state in place on said undercoat, said fused metal having a fusion temperature below the temperature at which degradation of said synthetic resin occurs.
Claim 7
Independent Claim
85 words
The method of forming a moisture impervious coating on composite structures which comprises the steps of: providing a composite structure comprising fibers embedded in a synthetic resin matrix; forming a metal undercoating over the structure surface; forming a top coat substantially free of open paths between its surfaces over said undercoat by solidifying a fused metal coating from an entirely fused state in place on said undercoat, said fused metal having a fusion temperature below the temperature at which degradation of said synthetic resin occurs.
Claim 8
Dependent Claim
26 words
The method according to claim 5 further including the step of uniformly abrading the surface of said structure prior to the formation of said metal undercoating.
Claim 9
Dependent Claim
26 words
The method according to claim 5 further including the step of cleaning the surface of said metal undercoating prior to the formation of said top coat.
Claim 10
Dependent Claim
35 words
The method according to claim 5 wherein said under-coating is formed by plating by electroless and electrolytic techniques a metal selected from the group consisting of copper, nickel chromium, silver and mixtures and multi-layers thereof.
Claim 11
Dependent Claim
23 words
The method according to claim 8 wherein said metal is copper plated to a thickness of from about 0.00025 to about 0.00035 inch.
Claim 12
Dependent Claim
30 words
The method according to claim 5 wherein said top coat comprises an eutectic mixture of at least two members of the group consisting of bismuth, tin, lead, indium, and cadmium.
Claim 13
Dependent Claim
30 words
The method according to claim 10 wherein said eutectic mixture comprises from about 48 to about 52 weight percent tin and from about 52 to about 48 weight percent indium.
Claim 14
Dependent Claim
41 words
The method according to claim 5 wherein said top coat is formed by directly contacting said structure with said fused metal in a fused state, to form a layer of entirely fused metal then cooling the structure to solidify the metal.
Claim 15
Dependent Claim
25 words
The method according to claim 5 further including the step of rapidly rotating said structure as said fused metal solidifies to sling off excess metal.
Claim 16
Dependent Claim
52 words
The method according to claim 5 wherein said top coat is formed by electroplating onto said undercoating at least one layer of each metal making up the top coating, heating the electroplated top coating above the fusion temperature of the top coating metals, then cooling the structure to solidify the top coating.
Claim 17
Independent Claim
137 words
The method of forming a moisture impervious coating on composite structures whichs comprises the steps of: providing a structure comprising graphite fibers embedded in a synthetic resin matrix material; abrading the structure surface to produce a uniform dull surface; forming an undercoat on said surface by electroless plating at least one metal selected from the group consisting of copper, nickel chromium, silver, mixtures thereof and multi-layers thereof; assuring a clean surface on said undercoat; forming a top coat over said undercoat by solidifying a fused metal coating in place on said undercoat, said fused metal coating comprising an eutectic mixture of at least two metals selected from the group consisting of bismuth, tin, lead, cadmium, and indium, the fusion temperature of said eutectic mixture being below the temperature at which damage to said synthetic resin matrix occurs.
Claim 18
Independent Claim
137 words
The method of forming a moisture impervious coating on composite structures whichs comprises the steps of: providing a structure comprising graphite fibers embedded in a synthetic resin matrix material; abrading the structure surface to produce a uniform dull surface; forming an undercoat on said surface by electroless plating at least one metal selected from the group consisting of copper, nickel chromium, silver, mixtures thereof and multi-layers thereof; assuring a clean surface on said undercoat; forming a top coat over said undercoat by solidifying a fused metal coating in place on said undercoat, said fused metal coating comprising an eutectic mixture of at least two metals selected from the group consisting of bismuth, tin, lead, cadmium, and indium, the fusion temperature of said eutectic mixture being below the temperature at which damage to said synthetic resin matrix occurs.
Claim 19
Dependent Claim
37 words
The method according to claim 15 wherein said top coat is formed by directly contacting said undercoat with fused metal, shaping the fused metal to a uniform coating of a selected thickness and solidifying the fused metal.
Claim 20
Dependent Claim
52 words
The method according to claim 15 wherein said top coat is formed by electroplating at least one layer of each of said at least two metals onto said undercoat, heating the electroplated top coat above the fusion temperature of said at least two metals, and solidifying the resulting fused metal top coat.
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) | 1980-05-09 | 1980-11-08 | 1981-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-09 | 1984-11-08 | 1985-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-09 | 1988-11-08 | 1989-05-10 | $7700.00 | Window Closed / Lapsed |