US4707312A
Expired / Lapsed
US
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Method for producing ceramic articles of increased fracture toughness
Assignee: PITTSBURGH/MATERIALS TECHNOLOGY Inc
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Filing: 1985-10-09
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Granted: 1987-11-17
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Expires: 2005-10-09
Abstract
Abstract Ceramic articles having improved fracture toughness are prepared by ion bombardment of ceramic particles by gas ions to impregnate the particles, cold compacting the gas ion-containing ceramic particles into a form, and hot pressing the gas ion-containing ceramic particle form into a ceramic article whereby gas bubbles are formed in and substantially homogeneously dispersed throughout the ceramic article.
Inventors
- 👤 Ram Bajaj
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:10
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/64; C04B35/645; C04B38/00
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
110 words
A method of producing ceramic articles having improved fracture toughness properties by a powder metallurgical process comprising: providing a supply of ceramic particles having a particle size of between 0.5-5 micrometers in diameter; injecting gas ions into the ceramic particles of said supply of particles by impingement therewith of a beam of accelerated said gas ions to produce a supply of gas ion-containing ceramic particles; cold compacting said gas ion-containing ceramic particles into a form by applying pressure thereabout; and heating said form at a temperature of at least 800° C., whereby said gas ions form gas bubbles, to produce a ceramic article having gas bubbles substantially uniformly disposed throughout.
Claim 2
Independent Claim
110 words
A method of producing ceramic articles having improved fracture toughness properties by a powder metallurgical process comprising: providing a supply of ceramic particles having a particle size of between 0.5-5 micrometers in diameter; injecting gas ions into the ceramic particles of said supply of particles by impingement therewith of a beam of accelerated said gas ions to produce a supply of gas ion-containing ceramic particles; cold compacting said gas ion-containing ceramic particles into a form by applying pressure thereabout; and heating said form at a temperature of at least 800° C., whereby said gas ions form gas bubbles, to produce a ceramic article having gas bubbles substantially uniformly disposed throughout.
Claim 3
Dependent Claim
28 words
The method as defined in claim 1 wherein said gas ions comprise ions of an inert gas selected from the group consisting of helium, argon, neon and krypton.
Claim 4
Dependent Claim
39 words
The method as defined in claim 1 wherein said heating under pressure produces a ceramic article having a c/r o ratio of between 0.1 to 5.0, wherein 2c is the interbubble spacing and 2r o is the bubble diameter.
Claim 5
Dependent Claim
31 words
The method as defined in claim 1 wherein said ceramic particles are selected from the group consisting of oxides, nitrides, borides and carbides of silicon, zirconium, aluminum, magnesium, yttrium, and SiAlON.
Claim 6
Dependent Claim
14 words
The method as defined in claim 4 wherein said ceramic particles comprise silicon nitride.
Claim 7
Dependent Claim
14 words
The method as defined in claim 4 wherein said ceramic particles comprise silicon carbide.
Claim 8
Dependent Claim
15 words
The method as defined in claim 4 wherein said ceramic particles comprise partially stabilized zirconia.
Claim 9
Dependent Claim
13 words
A method as defined in claim 4 wherein said ceramic particles comprise alumina.
Claim 10
Dependent Claim
13 words
The method as defined in claim 4 wherein said ceramic particles comprise SiAlON.
Claim 11
Dependent Claim
18 words
The method as defined in claim 1 wherein said heating of said form is effected under superatmospheric pressure.
Claim 12
Dependent Claim
37 words
The method as defined in claim 1 wherein said compacting of said gas ion-containing ceramic particles into a form is effected to provide a form having a density of about 65 to 80 percent of theoretical density.
Claim 13
Independent Claim
146 words
A method of producing ceramic articles having improved fracture toughness properties by a powder metallurgical process comprising: providing a supply of ceramic particles having a particle size of between 0.5-5 micrometer in diameter, said ceramic particles selected from the group consisting of oxides, nitrides and carbides of silicon, zirconium and aluminum; injecting inert gas ions, selected from the group consisting of ions of helium, argon, neon and krypton, into the ceramic particles of said supply of particles by impingement therewith of a beam of accelerated said inert gas ions to produce a supply of inert gas ion-containing ceramic particles; cold compacting said inert gas ion-containing ceramic particles into a form by applying pressure thereabout; and heating said form at a temperature of at least 800° C., whereby said inert gas ions form gas bubbles, to produce a ceramic article having gas bubbles substantially uniformly dispersed throughout.
Claim 14
Independent Claim
146 words
A method of producing ceramic articles having improved fracture toughness properties by a powder metallurgical process comprising: providing a supply of ceramic particles having a particle size of between 0.5-5 micrometer in diameter, said ceramic particles selected from the group consisting of oxides, nitrides and carbides of silicon, zirconium and aluminum; injecting inert gas ions, selected from the group consisting of ions of helium, argon, neon and krypton, into the ceramic particles of said supply of particles by impingement therewith of a beam of accelerated said inert gas ions to produce a supply of inert gas ion-containing ceramic particles; cold compacting said inert gas ion-containing ceramic particles into a form by applying pressure thereabout; and heating said form at a temperature of at least 800° C., whereby said inert gas ions form gas bubbles, to produce a ceramic article having gas bubbles substantially uniformly dispersed throughout.
Claim 15
Dependent Claim
39 words
The method as defined in claim 12 wherein said heating under pressure produces a ceramic article having a c/r o ratio of between 0.1 to 5.0, wherein 2c is the interbubble spacing and 2r o is the bubble diameter.
Claim 16
Dependent Claim
14 words
The method as defined in claim 13 wherein said ceramic particles comprise silicon nitride.
Claim 17
Dependent Claim
14 words
The method as defined in claim 13 wherein said ceramic particles comprise silicon carbide.
Claim 18
Dependent Claim
15 words
The method as defined in claim 13 wherein said ceramic particles comprise partially stabilized zirconia.
Claim 19
Dependent Claim
13 words
The method as defined in claim 13 wherein said ceramic particles comprise alumina.
Claim 20
Dependent Claim
38 words
The method as defined in claim 12 wherein said compacting of said inert gas ion-containing particles into a form is effected to provide a form having a density of about 65 to 80 percent of the theoretical density.
Claim 21
Dependent Claim
18 words
The method as defined in claim 12 wherein said heating of said form is effected under superatmospheric pressure.
Claim 22
Dependent Claim
21 words
The method as defined in claim 1 wherein said ceramic particles are a nitride and said gas ions are nitrogen ions.
Claim 23
Dependent Claim
21 words
The method as defined in claim 1 wherein said ceramic particles are an oxide and said gas ions are oxygen ions.
Claim 24
Dependent Claim
21 words
The method as defined in claim 1 wherein said particles are tumbled in a vacuum at ambient temperature during said impingement.
Claim 25
Dependent Claim
17 words
The method as defined in claim 1 wherein gas ions have an energy of about 150 KeV.
Claim 26
Dependent Claim
20 words
The method as defined in claim 1 wherein said gas bubbles are about 100 to about 400 Angstroms in diameter.
Claim 27
Independent Claim
74 words
A method of producing a ceramic article having improved fracture toughness comprising: (A) injecting ions of an inert gas into ceramic particles that have a diameter of about 0.5 to about 5 microns to produce gas ion-containing ceramic particles; (B) cold compacting said ceramic particles; and (C) heating said cold compacted particles to a temperature, at least 800° C., sufficient to fuse them into a ceramic article having gas bubbles substantially uniformly disposed throughout.
Claim 28
Independent Claim
74 words
A method of producing a ceramic article having improved fracture toughness comprising: (A) injecting ions of an inert gas into ceramic particles that have a diameter of about 0.5 to about 5 microns to produce gas ion-containing ceramic particles; (B) cold compacting said ceramic particles; and (C) heating said cold compacted particles to a temperature, at least 800° C., sufficient to fuse them into a ceramic article having gas bubbles substantially uniformly disposed throughout.
References Cited (Backward Citations)
DE1646560A1
Cited
US4563432A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |