US4322249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of dispersion ceramics
Assignee: Max-Planck-Gesellschaft zur Förderung der Wissenschaften eV
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Filing: 1980-07-14
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Granted: 1982-03-30
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Expires: 2000-07-14
Abstract
Abstract In a process for the production of dispersion ceramics by sintering or hot pressing of a mixture of a matrix-forming ceramic material and of at least one ceramic embedment material dispersible therein which at the sintering temperature of the ceramic and at room temperature is present in different enantiotropic solid modifications of different densities, a ceramic embedment material is employed which is divided into at least two groups of different, substantially uniform particle sizes, each group having different lower phase-transition temperatures.
Inventors
- 👤 Nils Claussen
- 👤 Jurgen Jahn
- 👤 Gunter Petzow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:21
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/01; C04B35/10; C04B35/111; C04B35/117; C04B35/119; C04B35/575; C04B35/58; C04B35/584; C04B35/593
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
93 words
In a process for the production of dispersion ceramics by sintering or hot-pressing a mixture of a matrix-forming ceramic material, the improvement comprising the steps of dispersing throughout said matrix forming material at least one ceramic embedment material, the particles of which range in size from 0.1 to 5μ, which is present in different enantiotropic solid modifications of different densities at different predetermined temperatures and in the form of particles having a predetermined distribution of differently sized particles whereby the particles have a predetermined distribution of different lower phase-transition temperature T u .
Claim 2
Dependent Claim
93 words
In a process for the production of dispersion ceramics by sintering or hot-pressing a mixture of a matrix-forming ceramic material, the improvement comprising the steps of dispersing throughout said matrix forming material at least one ceramic embedment material, the particles of which range in size from 0.1 to 5μ, which is present in different enantiotropic solid modifications of different densities at different predetermined temperatures and in the form of particles having a predetermined distribution of differently sized particles whereby the particles have a predetermined distribution of different lower phase-transition temperature T u .
Claim 3
Dependent Claim
26 words
Improvement as claimed in claim 1, wherein the ceramic embedment material is employed in the form of agglomerates having different lower phase-transition temperatures T u .
Claim 4
Dependent Claim
21 words
Improvement as claimed in claim 1 wherein aluminum oxide, silicon carbide or silicon nitride is employed as the matrix-forming ceramic material.
Claim 5
Dependent Claim
19 words
Improvement as claimed in claim 1 wherrein unstabilized zirconium dioxide or hafnium dioxide is employed as ceramic embedment material.
Claim 6
Dependent Claim
27 words
Improvement as claimed in claim 1 wherein the size ratio of the smallest particles to the largest particles of the ceramic embedment material is at least 1:10.
Claim 7
Dependent Claim
42 words
Process as recited in claim 1, wherein ceramic embedment material is used comprising a mixture of at least two agglomerated mixtures of matrix material and embedment material, wherein the embedment material of each agglomerated mixture has a different, substantially uniform particle size.
Claim 8
Dependent Claim
90 words
In a dispersion ceramic material of the type formed of aluminum oxide, silicon carbide, or silicon nitride and having an embedment material of unstabilized zirconium dioxide or hafnium dioxide powder dispersed therethrough, the improvement comprising said embedment material, the particles of which range in size from 0.1 to 5μ, having first and second approximately equal volume portions of particles with a predetermined average size variation ratio of the particles in said first portion to said second portion of at least 1:10 to give the ceramic material enhanced thermal shock resistance.
Claim 9
Dependent Claim
90 words
In a dispersion ceramic material of the type formed of aluminum oxide, silicon carbide, or silicon nitride and having an embedment material of unstabilized zirconium dioxide or hafnium dioxide powder dispersed therethrough, the improvement comprising said embedment material, the particles of which range in size from 0.1 to 5μ, having first and second approximately equal volume portions of particles with a predetermined average size variation ratio of the particles in said first portion to said second portion of at least 1:10 to give the ceramic material enhanced thermal shock resistance.
Claim 10
Dependent Claim
42 words
The ceramic material of claim 7 wherein there are intermediate portions of embedment material particles intermediate in size to the particles of said first and second portions, said intermediate portions being of approximately the same volume as said first or second portions.
Claim 11
Dependent Claim
17 words
Improvement as claimed in claim 1, wherein unstabilized zirconium dioxide is employed as the ceramic embedment material.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-29 | 1985-09-28 | 1986-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-29 | 1989-09-28 | 1990-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-29 | 1993-09-28 | 1994-03-30 | $7700.00 | Window Closed / Lapsed |