US4718941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infiltration processing of boron carbide-, boron-, and boride-reactive metal cermets
Assignee: University of California, San Diego
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Filing: 1986-06-17
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Granted: 1988-01-12
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Expires: 2006-06-17
Abstract
Abstract A chemical pretreatment method is used to produce boron carbide-, boron-, and boride-reactive metal composites by an infiltration process. The boron carbide or other starting constituents, in powder form, are immersed in various alcohols, or other chemical agents, to change the surface chemistry of the starting constituents. The chemically treated starting constituents are consolidated into a porous ceramic precursor which is then infiltrated by molten aluminum or other metal by heating to wetting conditions. Chemical treatment of the starting constituents allows infiltration to full density. The infiltrated precursor is further heat treated to produce a tailorable microstructure. The process at low cost produces composites with improved characteristics, including increased toughness, strength.
Inventors
- 👤 Danny C. Halverson
- 👤 Richard L. Landingham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:19
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B35/00; C04B35/515; C04B35/56; C04B35/563; C04B35/622; C04B35/64; C04B35/65; C04B35/652; C04B38/00; C04B41/45; C04B41/50; C04B41/51
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
113 words
A method of fabricating metal-ceramic composites from previously formed ceramic precursor starting constituents selected from boron-carbide, boron and borides and metals reactive therewith selected from reactive metals, alloys thereof, and compounds thereof which reduce to reactive metals or alloys thereof, comprising: chemically pretreating the previously formed starting constituents of a ceramic precursor; consolidating the chemically pretreated starting constituents into a porous ceramic precursor; infiltrating molten reactive metal into the chemically pretreated ceramic precursor; wherein the step of chemically pretreating the starting constituents of the ceramic precursor alters the surface chemistry to enhance infiltration of the precursor by the molten reactive metal by slowing the kinetics of reaction relative to the kinetics of densification.
Claim 2
Independent Claim
113 words
A method of fabricating metal-ceramic composites from previously formed ceramic precursor starting constituents selected from boron-carbide, boron and borides and metals reactive therewith selected from reactive metals, alloys thereof, and compounds thereof which reduce to reactive metals or alloys thereof, comprising: chemically pretreating the previously formed starting constituents of a ceramic precursor; consolidating the chemically pretreated starting constituents into a porous ceramic precursor; infiltrating molten reactive metal into the chemically pretreated ceramic precursor; wherein the step of chemically pretreating the starting constituents of the ceramic precursor alters the surface chemistry to enhance infiltration of the precursor by the molten reactive metal by slowing the kinetics of reaction relative to the kinetics of densification.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein the step of chemically pretreating the starting constituents comprises chemically altering the surface chemistry of the starting constituents to eliminate phases which inhibit infiltration.
Claim 4
Dependent Claim
26 words
The method of claim 2 wherein the step of chemically pretreating the starting constituents comprises chemically converting phases which inhibit infiltration to phases which promote infiltration.
Claim 5
Dependent Claim
15 words
The method of claim 3 further including pyrolyzing the chemically converted phases at low temperature.
Claim 6
Dependent Claim
17 words
The method of claim 1 further comprising forming the starting constituents into particles prior to chemically pretreating.
Claim 7
Dependent Claim
16 words
The method of claim 5 further comprising forming the particles with a controlled polymodal size distribution.
Claim 8
Dependent Claim
18 words
The method of claim 1 wherein the step of consolidating the starting constituents is performed by colloidal consolidation.
Claim 9
Dependent Claim
18 words
The method of claim 6 wherein the step of consolidating the starting constituents is performed by colloidal consolidation.
Claim 10
Dependent Claim
30 words
The method of claim 1 wherein the steps of pretreating and consolidating the starting constitutents are performed by injection molding the starting constituents using a binder containing chemical pretreatment agents.
Claim 11
Dependent Claim
32 words
The method of claim 1 wherein the step of pretreatment is performed by immersing the starting constituents in a chemical solution to produce chemical reactions at the surface of the starting constituents.
Claim 12
Dependent Claim
23 words
The method of claim 10 for boron-carbide starting constituents comprising changing the boron to carbon ratio at the surface of the starting constituents.
Claim 13
Dependent Claim
32 words
The method of claim 1 comprising chemically removing B 2 O 3 , BH 3 O 3 and B 2 O 3 ·H 2 O from the surface of the starting constituents.
Claim 14
Dependent Claim
444 words
The method of claim 10 comprising immersing the starting constituents in any of the following: a. methanol (CH 4 O or CH 3 OH); b. anhydrous alcohol (C 2 H 6 OH); c. n-propyl alcohol (C 3 H 8 O or CH 3 CH 2 CH 2 OH); d. isopropyl alcohol (C 3 H 8 O or CH 3 HOHCH 3 ); e. n-butyl alcohol (C 4 H 10 O or CH 3 CH 2 CH 2 CH 2 OH); f. sec-butyl alcohol (C 4 H 10 O or CH 3 CH 2 CH(OH)CH 3 ); g. tert-butyl alcohol C 4 H 10 O or (CH 3 ) 3 COH); h. any azeotrope of the above; i. any dilution of the the above; j. any higher alcohol (C n H m O), where n ≧4 and m ≧10), or azeotrope or dilution thereof; k. glycerol (C 3 H 8 O 3 or CH 20 OHCHOHCH 2 OH); 1. any glycerol derivative (C n H m O p , where n ≧3,m ≧6,and p ≧2), including glyceraldehyde (C 3 H 6 O 3 ), glyceric acid (C 3 H 6 O 4 or CH 2 OHCH(OH)COOH), glycerol formal (C 4 H 8 O 3 ), and glycidol (C 3 H 6 O 2 ); m. any methyl--abietate (C 21 H 32 O 2 ), acetate (C 3 H 6 O 2 or CH 3 COOCH 3 ), acetoacetate (C 3 H 8 O 3 or CH 3 COCH 2 COOCH 3 ), acetylsalicylate (C 10 H 10 O 4 ), acrylate (C 4 H 6 O 2 or CH 2 =CHCOOCH 3 ), benzoate (C 8 H 8 O 2 or C 6 H 5 COOCH 3 ), benzoylsalicylate (C 15 H 12 O 4 ), butyl ketone (C 6 H 12 O.sub. or CH 3 COC 4 H 9 ), butyrate (C 5 H 10 O 2 or CH 3 (CH 2 ) 2 COOCH 3 ), carbitol (C 5 H 12 O 3 or CH 3 OCH 2 CH 2 OCH 2 CH 2 OH), carbonate (C 3 H 6 O 3 or CO(OCH 3 ) 2 ), cellosolve (C 3 H 8 O 2 or HOCH 2 CH 2 OCH 3 ), cellosolve acetate (C 5 H 10 O 3 or CH 3 OCH 2 CH 2 OOCCH 3 ), or methylcellulose, or methylal (C 3 H.sub. 8 O 2 or CH 2 (OCH 3 ) 2 ); n. boiling water; o. cold water; p. any combination of the above, in part or whole; q. any binder, for the purpose of injection molding, containing any of the above, in part or whole.
Claim 15
Dependent Claim
40 words
The method of claim 1 wherein the step of infiltrating the metal into the precursor comprises: placing the metal adjacent to the precursor; heating the metal and precursor to a temperature which promotes wetting of the precursor by the metal.
Claim 16
Dependent Claim
14 words
The method of claim 14 wherein the heating step is performed in a vacuum.
Claim 17
Dependent Claim
15 words
The method of claim 14 wherein the heating step is performed in an inert atmosphere.
Claim 18
Dependent Claim
19 words
The method of claim 14 further comprising further heating to a temperature which promotes microstructural enhancement of the composite.
Claim 19
Dependent Claim
11 words
The method of claim 1 further comprising forming a graded microstructure.
Claim 20
Dependent Claim
11 words
The method of claim 7 further comprising forming a graded microstructure.
Claim 21
Dependent Claim
19 words
The method of claim 1 further comprising consolidating the starting constituents into a precursor having a substantially disconnected microstructure.
Claim 22
Dependent Claim
9 words
A composite formed by the method of claim 1.
Claim 23
Dependent Claim
9 words
A composite formed by the method of claim 13.
Claim 24
Dependent Claim
9 words
A composite formed by the method of claim 18.
Claim 25
Dependent Claim
9 words
A composite formed by the method of claim 20.
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) | 1991-01-11 | 1991-07-13 | 1992-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-11 | 1995-07-13 | 1996-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-11 | 1999-07-13 | 2000-01-12 | $7700.00 | Window Closed / Lapsed |