EP0179670A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Production of silicon carbide cobweb whiskers
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1985-10-25
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Granted: —
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Expires: 2005-10-25
Abstract
Abstract Silicon carbide cobweb whiskers are produced by heating a mixture of silicon dioxide powder, carbon powder and a catalyst composed of at least one of niobium, tantalum and compounds thereof in a non-oxidative gas at a temperature of from 1,400 to 1,900°C.
Inventors
- 👤 Tadanori Hashimoto
- 👤 Kazuhiko Nakano
- 👤 Norio Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 07:16
CPC Classifications
C; C30; C30B; C30B25/00; C30B25/005; C30B29/00; C30B29/10; C30B29/36
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
66 words
A method of producing silicon carbide cobweb whiskers by reductive carbonisation of silicon dioxide characterised in that a mixture of a silicon dioxide powder, a carbon powder, and a catalyst composed of at least one of niobium, tantalum and compounds thereof is heated in a non-oxidative gas at a temperature of from 1,400 to 1,900°C, to produce silicon carbide cobweb whiskers among particles of unreacted carbon.
Claim 2
Independent Claim
66 words
A method of producing silicon carbide cobweb whiskers by reductive carbonisation of silicon dioxide characterised in that a mixture of a silicon dioxide powder, a carbon powder, and a catalyst composed of at least one of niobium, tantalum and compounds thereof is heated in a non-oxidative gas at a temperature of from 1,400 to 1,900°C, to produce silicon carbide cobweb whiskers among particles of unreacted carbon.
Claim 3
Dependent Claim
27 words
A method according to claim 1, wherein the amount of carbon powder is from 0.6 to 3 parts per part of said silicon dioxide powder by weight.
Claim 4
Dependent Claim
39 words
A method according to claim 1 or 2, wherein the amount of catalyst is from 0.0001 to 0.1 part, based on the total weight of niobium and tantalum as elements, per part by weight of said silicon dioxide powder.
Claim 5
Dependent Claim
29 words
A method according to claim 1, 2 or 3, wherein the mixture is heated at a temperature of from 1,450 to 1,800°C in an atmosphere of argon and/or hydrogen.
Claim 6
Dependent Claim
29 words
A method according to claim 1, 2 or 3, wherein the mixture is heated at a temperature of from 1,600 to 1,800°C in an atmosphere of a nitrogen-containing gas.
Claim 7
Dependent Claim
14 words
A method according to claim 5, wherein the nitrogen-containing gas is nitrogen and/or ammonia.
Claim 8
Independent Claim
40 words
A method according to any preceding claim, wherein the unreacted carbon is removed by subsequently heating the mixture of silicon carbide cobweb whiskers and unreacted carbon at a temperature of from 600 to 800°C in an atmosphere of oxidative gas.
Claim 9
Dependent Claim
14 words
A method according to claim 7, wherein the oxidative gas is oxygen or air.
Claim 10
Independent Claim
22 words
A method according to any preceding claim, wherein the catalyst is composed of at least one of niobium pentoxide and tantalum pentoxide.
Claim 11
Dependent Claim
14 words
Silicon carbide cobweb whiskers having a mean diameter of from 0.1 to 1.0 µm.
Claim 12
Dependent Claim
14 words
Silicon carbide cobweb whiskers having a mean diameter of from 0.1 to 1.0 µm.
References Cited (Backward Citations)
No citation records indexed.
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