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Patent US4540677A successfully refreshed from Google Patents.
US4540677A
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Process for producing a power composition for producing sintered ceramic articles
Assignee: Ibiden Co Ltd
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Filing: 1984-09-27
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Granted: 1985-09-10
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Expires: 2004-09-27
Abstract
Abstract A powder composition for producing sintered ceramic, which composition contains fluororesin powder which has not been used in the prior art as one of the materials constituting a molding assistant to be blended in the composition. With this composition, it is possible to produce a high-density green molding with few molding defects under a relatively low molding pressure. The invention also provides a process for producing such a composition.
Inventors
- 👤 Ryo Enomoto
- 👤 Kiyotaka Tsukada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:43
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/63; C04B35/632; C04B35/634; C04B35/63404; C04B35/63436; C04B35/01; C04B35/10; C04B35/111; C04B35/515; C04B35/56; C04B35/565; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
178 words
A process for producing a powder composition for producing sintered ceramic, which comprises supplying 100 parts by weight of a ceramic powder composed of one or more components and 0.5 to 15 parts by weight of a fluororesin to a liquid dispersion medium so that the volume ratio of solid matter consisting of said ceramic powder and fluororesin in the suspension will be within the range from 5 to 501, subjecting the mixture to a uniform dispersion treatment by adding a dispersant, giving to said suspension a pressure difference enough to overcome the stagnation of a sieving action due to a pressure less caused between the portions of the suspension on the fore and the rear sides of the sieve, passing the suspension through a sieve having a mesh size of 65 μm or less by giving vibrations to the suspension, and after the sieving treatment making the suspension into grannules having a powder bulk density equivalent to 5 to 46% of the theoretical value, and an average particle size within the range from 0.02 to 0.8 mm.
Claim 2
Dependent Claim
178 words
A process for producing a powder composition for producing sintered ceramic, which comprises supplying 100 parts by weight of a ceramic powder composed of one or more components and 0.5 to 15 parts by weight of a fluororesin to a liquid dispersion medium so that the volume ratio of solid matter consisting of said ceramic powder and fluororesin in the suspension will be within the range from 5 to 501, subjecting the mixture to a uniform dispersion treatment by adding a dispersant, giving to said suspension a pressure difference enough to overcome the stagnation of a sieving action due to a pressure less caused between the portions of the suspension on the fore and the rear sides of the sieve, passing the suspension through a sieve having a mesh size of 65 μm or less by giving vibrations to the suspension, and after the sieving treatment making the suspension into grannules having a powder bulk density equivalent to 5 to 46% of the theoretical value, and an average particle size within the range from 0.02 to 0.8 mm.
Claim 3
Dependent Claim
25 words
A process according to claim 1 wherein said fluororesin is at least one substance selected from polytetrafluoroethylene, polytrifluorochloroethylene, tetrafluoroethylene/hexafluoropropylene copolymer, polyvinylidene fluoride, and ethylene/fluoroethylene copolymer.
Claim 4
Dependent Claim
26 words
A process according to claim 1 or 2 wherein said fluororesin is a finely divided powder having an average particle size of 3 μm or less.
Claim 5
Dependent Claim
29 words
A process according to claim 1 or 2 wherein said ceramic powder comprises as its principal component at least one substance selected from carbides, nitrides, oxides and compounds thereof.
Claim 6
Dependent Claim
26 words
A process according to claim 1 or 2 wherein said ceramic powder is finely divided powder having an average particle size of 2 μm or less.
Claim 7
Dependent Claim
36 words
A process according to claim 1 or 2 wherein said ceramic powder is composed principally of silicon carbide powder having a specific surface area of 5 to 100 m 2 /g and an added sintering assistant.
Claim 8
Dependent Claim
47 words
A process according to claim 1 or 2 wherein said dispersion medium is at least one substance selected from acetone, methanol, ethanol, hexane, heptane, nonane, toluene, xylene, ethyl methyl ketone, methyl isobutyl ketone, ethylbenzene, ethylene glycol, trichloroethylene, cyclohexane, nitromethane, nitroethane, isopropyl alcohol, benzene, carbon tetrachloride and water.
Claim 9
Dependent Claim
41 words
A process according to claim 1 or 2 wherein said dispersant is added in an amount within the range from 0.05 to 15 parts by weight to 100 parts by weight of the total amount of the ceramic powder and fluororesin.
Claim 10
Dependent Claim
41 words
A process according to claim 1 or 2 wherein said pressure difference between the portions of the suspension on the fore and the rear sides of the sieve is varied at a period within the range from 1/400 to 5 seconds.
Claim 11
Dependent Claim
23 words
A process according to claim 1 or 2 wherein said suspension is given a vibration at a frequency of 1 to 400 Hz.
References Cited (Backward Citations)
US2593507A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |