US4526734A
Expired / Lapsed
US
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Process for the production of silicon carbide sintered bodies
Assignee: Ibiden Co Ltd
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Filing: 1982-02-26
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Granted: 1985-07-02
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Expires: 2002-02-26
Abstract
Abstract A process for producing a silicon carbide sintered body is disclosed, which comprises the steps of charging a sintering raw material consisting mainly of silicon carbide fine powder and sintering aid into a dispersion medium together with, if necessary, at least one substance of a molding assistant and a deflocculating agent to form such a uniform suspension that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; spray freezing said suspension in an atmosphere held at a temperature lower than a melting point of said dispersion medium to obtain a granular frozen body; freeze drying said granular frozen body for sublimation of said dispersion medium to obtain a powdery dried mixture; shaping said powdery dried mixture into a green body of an optional form; and sintering said green body without pressing.
Inventors
- 👤 Ryo Enomoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:52
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
160 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a substance selected from a group consisting of a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates: (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optical form; and (e) sintering said green body without pressing.
Claim 2
Dependent Claim
160 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a substance selected from a group consisting of a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates: (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optical form; and (e) sintering said green body without pressing.
Claim 3
Dependent Claim
28 words
A process according to claim 1, wherein said atmosphere is held at a temperature of at least 5° C. lower than said melting temperature of the dispersion medium.
Claim 4
Dependent Claim
30 words
A process according to claim 2, wherein said temperature of the atmosphere is within a range of 10° to 100° C. lower than said melting temperature of the dispersion medium.
Claim 5
Dependent Claim
20 words
A process according to claim 1, wherein said dispersion medium has a melting point of -5° C. to 15° C.
Claim 6
Dependent Claim
46 words
A process according to claim 1, wherein said suspension is maintained in a uniform dispersed state by a means selected from the group consisting of vibration means and agitation means and said means continuously function until at least two minutes prior to spray freezing said suspension.
Claim 7
Dependent Claim
159 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a substance selected from a group consisting of a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 8
Dependent Claim
159 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a substance selected from a group consisting of a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 9
Dependent Claim
28 words
A process according to claim 6, wherein said suspension is concentrated by evaporation while maintaining the uniform dispersed state by at least one means of vibration and agitation.
Claim 10
Dependent Claim
31 words
A process according to claim 6 or 7, wherein said volume ratio of solid content in the spray freezing of said suspension is more than 15% but not more than 50%.
Claim 11
Dependent Claim
21 words
A process according to claim 8, wherein said volume ratio of solid content is within a range of 20 to 45%.
Claim 12
Dependent Claim
23 words
A process according to claim 6, wherein said dispersion medium has a melting point within a range of -5° C. to 15° C.
Claim 13
Dependent Claim
28 words
A process according to claim 6, wherein said atmosphere is held at a temperature of at least 5° C. lower than said melting temperature of the dispersion medium.
Claim 14
Dependent Claim
30 words
A process according to claim 11, wherein said temperature of the atmosphere is within a range of 10° to 100° C. lower than said melting temperature of the dispersion medium.
Claim 15
Dependent Claim
46 words
A process according to claim 6, wherein said suspension is maintained in a uniform dispersed state by a means selected from the group consisting of vibration means and agitation means and said means continuously function until at least two minutes prior to spray freezing said suspension.
Claim 16
Dependent Claim
21 words
A process according to claim 6, wherein said powdery dried mixture has an average grain size of 0.02 to 0.5 mm.
Claim 17
Dependent Claim
23 words
A process according to claim 6, wherein said powdery dried mixture has a powder bulk density of 0.4 to 1.2 g/cm 3 .
Claim 18
Dependent Claim
18 words
A process according to claim 15, wherein said powder bulk density is 0.6 to 1.0 g/cm 3 .
Claim 19
Dependent Claim
143 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 20
Dependent Claim
143 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 21
Dependent Claim
28 words
A process according to claim 17, wherein a substance selected from a group consisting of a molding assistant and a deflocculating agent are added to said dispersion medium.
Claim 22
Dependent Claim
21 words
A process according to claim 17, wherein a molding assistant and a deflocculating agent are both added to the dispersion medium.
Claim 23
Dependent Claim
28 words
A process according to claim 17, wherein said atmosphere is held at a temperature of at least 5° C. lower than said melting temperature of the dispersion medium.
Claim 24
Dependent Claim
31 words
A process according to claim 20, wherein said temperature of the atmosphere is within a range of 10° C. to 100° C. lower than said melting temperature of the dispersion medium.
Claim 25
Dependent Claim
20 words
A process according to claim 17, wherein said dispersion medium has a melting point of -5° C. to 15° C.
Claim 26
Dependent Claim
46 words
A process according to claim 17, wherein said suspension is maintained in a uniform dispersed state by a means selected from the group consisting of vibration means and agitation means and said means continuously function until at least two minutes prior to spray freezing said suspension.
Claim 27
Dependent Claim
152 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 28
Dependent Claim
152 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 29
Dependent Claim
142 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 30
Dependent Claim
142 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 31
Dependent Claim
28 words
A process according to claim 25, wherein a substance selected from a group consisting of a molding assistant and a deflocculating agent are added to the dispersion medium.
Claim 32
Dependent Claim
21 words
A process according to claim 25, wherein a molding assistant and a deflocculating agent are both added to the dispersion medium.
Claim 33
Dependent Claim
35 words
A process according to claim 25, wherein said suspension is concentrated by evaporation while maintaining the uniformed dispersed state by at least one means selected from the group consisting of vibration means and agitation means.
Claim 34
Dependent Claim
29 words
A process according to claim 25, wherein said volume ratio of solid content in the spray freezing of said suspension is more than 15% but not more than 50%.
Claim 35
Dependent Claim
29 words
A process according to claim 28, wherein said volume ratio of solid content in the spray freezing of said suspension is more than 15% but not more than 50%.
Claim 36
Dependent Claim
21 words
A process according to claim 29, wherein said volume ratio of solid content is within a range of 20% to 45%.
Claim 37
Dependent Claim
21 words
A process according to claim 30, wherein said volume ratio of solid content is within a range of 20% to 45%.
Claim 38
Dependent Claim
23 words
A process according to claim 25, wherein said dispersion medium has a melting point within a range of -5° C. to 15° C.
Claim 39
Dependent Claim
28 words
A process according to claim 25, wherein said atmosphere is held at a temperature of at least 5° C. lower than said melting temperature of the dispersion medium.
Claim 40
Dependent Claim
31 words
A process according to claim 34, wherein said temperature of the atmosphere is within a range of 10° C. to 100° C. lower than said melting temperature of the dispersion medium.
Claim 41
Dependent Claim
46 words
A process according to claim 25, wherein said suspension is maintained in a uniform dispersed state by a means selected from the group consisting of vibration means and agitation means and said means continuously function until at least two minutes prior to spray freezing said suspension.
Claim 42
Dependent Claim
21 words
A process according to claim 25, wherein said powdery dried mixture has an average grain size of 0.02 to 0.5 mm.
Claim 43
Dependent Claim
23 words
A process according to claim 25, wherein said powdery dried mixture has a powder bulk density of 0.4 to 1.2 g/cm 3 .
Claim 44
Dependent Claim
18 words
A process according to claim 38, wherein said powder bulk density is 0.6 to 1.0 g/cm 3 .
Claim 45
Dependent Claim
151 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 46
Dependent Claim
151 words
A process for producing a silicon carbide sintered body comprising the steps of: (a) charging a sintering raw material consisting essentially of a substantially non-soluble silicon carbide fine powder and a sintering aid into a dispersion medium selected from the group consisting of benzene, cyclohexane and water, together with a molding assistant and a deflocculating agent to form a uniform suspension such that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is more than 15%; (b) spray freezing said suspension in an atmosphere held at a temperature lower than a melting temperature of said dispersion medium to obtain frozen granulates; (c) freeze drying said frozen granulates for sublimation of said dispersion medium to obtain a powdery dried mixture; (d) shaping said powdery dried mixture into a green body of an optional form; and (e) sintering said green body without pressing.
Claim 47
Dependent Claim
76 words
A process according to claim 1, wherein said suspension is spray frozen in the form of droplets satisfying a relationship expressed by the following equation: ##EQU2## wherein X is an average diameter of said droplet sprayed (mm), Q is a heat quantity to be taken in the freezing of the suspension per unit volume (cal/cm 3 ), M is a melting point of the dispersion medium (°C.) and T is a temperature of the atmosphere (°C.).
Claim 48
Dependent Claim
76 words
A process according to claim 6, wherein said suspension is spray frozen in the form of droplets satisfying a relationship expressed by the following equation: ##EQU3## wherein X is an average diameter of said droplet sprayed (mm), Q is a heat quantity to be taken in the freezing of the suspension per unit volume (cal/cm 3 ), M is a melting point of the dispersion medium (°C.) and T is a temperature of the atmosphere (°C.).
Claim 49
Dependent Claim
76 words
A process according to claim 17, wherein said suspension is spray frozen in the form of droplets satisfying a relationship expressed by the following equation: ##EQU4## wherein X is an average diameter of said droplet sprayed (mm), Q is a heat quantity to be taken in the freezing of the suspension per unit volume (cal/cm 3 ), M is a melting point of the dispersion medium (°C.) and T is a temperature of the atmosphere (°C.).
Claim 50
Dependent Claim
76 words
A process according to claim 25, wherein said suspension is spray frozen in the form of droplets satisfying a relationship expressed by the following equation: ##EQU5## wherein X is an average diameter of said droplet sprayed (mm), Q is a heat quantity to be taken in the freezing of the suspension per unit volume (cal/cm 3 ), M is a melting point of the dispersion medium (°C.) and T is a temperature of the atmosphere (°C.).
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) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |