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US3743003A
Expired / Lapsed
US
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Making investment shell molds inhibited against reaction with molten reactive and refractory casting metals
Assignee: Selmet Inc
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Filing: 1971-06-03
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Granted: 1973-07-03
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Expires: 1991-06-03
Abstract
Abstract An investment shell mold inhibited against reaction with molten titanium, zirconium and other reactive and refractory metals cast therein is made by investing a pattern with successive dip coats and stucco coats. The first dip coat includes a tungsten and/or molybdenum compound inhibitor-former which is reducible by hydrogen to metallic tungsten or molybdenum. After removal of the pattern, the green mold is dried and then pyrolyzed in an atmosphere of hydrogen under conditions predetermined to convert the inhibitor-former to metallic condition. This creates on the mold interface a coating of metallic molybdenum or tunsten which serves as a physical barrier, inhibiting reaction of a molten reactive or refractory metal subsequently cast in the mold, with the mold material and binder particles of the latter.
Inventors
- 👤 R Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:31
CPC Classifications
B; B22; B22C; B22C1/00; B22C1/16; B22C1/165; B22C3/00
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
24 words
The method of claim 1 wherein the inhibitor-former comprises at least one member of the group consisting of the oxides of tungsten and molybdenum.
Claim 2
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises tungsten oxide.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises molybdenum oxide.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein the inhibitor-former comprises at least one member of the group consisting of tungstic acid, molybdic acid and the salts thereof.
Claim 5
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises tungstic acid.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises molybdic acid.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises ammonium metatungstate.
Claim 8
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises lanthanum metatungstate.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein the inhibitor-former comprises at least one member of the group consisting of the alkoxides and halogenated alkoxides of tungsten and molybdenum.
Claim 10
Dependent Claim
12 words
The method of claim 1 wherein the inhibitor-former comprises molybdenum chloroethoxide ethylate.
Claim 11
Dependent Claim
12 words
The method of claim 1 wherein the inhibitor-former comprises tungsten chloroethoxide ethylate.
Claim 12
Dependent Claim
26 words
The method of claim 1 wherein the inhibitor-former comprises at least one member of the group consisting of the halides and oxyhalides of tungsten and molybdenum.
Claim 13
Dependent Claim
11 words
The method of claim 13 wherein the halide comprises a chloride.
Claim 14
Dependent Claim
11 words
The method of claim 13 wherein the oxyhalide comprises an oxychloride.
Claim 15
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises tungsten chloride.
Claim 16
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises tungsten oxychloride.
Claim 17
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises molybdenum chloride.
Claim 18
Dependent Claim
11 words
The method of claim 1 wherein the inhibitor-former comprises molybdenum oxychloride.
Claim 19
Dependent Claim
24 words
The method of claim 1 wherein included in the first dip coat is a quantity of tungsten in the form of a metallic powder.
Claim 20
Dependent Claim
24 words
The method of claim 1 wherein included in the first dip coat is a quantity of molybdenum in the form of a metallic powder.
Claim 21
Dependent Claim
30 words
The method of claim 1 wherein the shell is heat cured in a purging atmosphere of hydrogen for substantially complete removal of the gaseous hydrogenation by-products from the mold environment.
Claim 22
Dependent Claim
21 words
The method of claim 1 wherein the mold is heat cured in an atmosphere of hydrogen admixed with an inert gas.
Claim 23
Dependent Claim
17 words
The method of claim 1 wherein the mold is heat cured in an atmosphere of cracked ammonia.
Claim 24
Dependent Claim
33 words
The method of claim 1 wherein the shell is heat cured in an atmosphere of hydrogen at a temperature of from 900*K. to 2500*K. for a time of from 2 to 4 hours.
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) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |