| 54 |
Title |
TI |
[DE] Verfahren zur Herstellung von Siliciumcarbid-Grünkörpern
[EN] Silicon carbide prods. for sintered ceramics prodn. - by electrophoresis of suspension of alpha-silicon carbide in polar aprotic solvent in presence of boron carbide, carbon and dispersant |
| 71/73 |
Applicant/owner |
PA |
Institut für neue Materialien gemeinnützige GmbH, 6600 Saarbrücken, DE
|
| 72 |
Inventor |
IN |
Meisel, Rainer Leo, 6600 Saarbrücken, DE
;
Naß, Rüdiger, Dipl.-Chem. Dr., 6601 Riegelsberg, DE
;
Schmidt, Helmut, Prof. Dr., 6604 Saarbrücken, DE
|
| 22/96 |
Application date |
AD |
Apr 14, 1992 |
| 21 |
Application number |
AN |
4212514 |
|
Country of application |
AC |
DE |
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Publication date |
PUB |
Oct 21, 1993 |
33
31
32 |
Priority data |
PRC
PRN
PRD |
|
| 51 |
IPC main class |
ICM |
C04B 35/56
|
| 51 |
IPC secondary class |
ICS |
C25B 1/00
C25B 7/00
|
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IPC additional class |
ICA |
|
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IPC index class |
ICI |
|
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Cooperative patent classification |
CPC |
C04B 35/565
C25B 7/00
|
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MCD main class |
MCM |
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MCD secondary class |
MCS |
C04B 35/565
(2006.01)
C25B 7/00
(2006.01)
|
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MCD additional class |
MCA |
|
| 57 |
Abstract |
AB |
[DE] Beschrieben wird ein Verfahren zur Herstellung von Siliciumcarbid-Grünkörpern, das dadurch gekennzeichnet ist, daß man eine Suspension von teilchenförmigem α-Siliciumcarbid in einem polaren aprotischen Lösungsmittel in Anwesenheit von feinteiligem Borcarbid und feinteiligem Kohlenstoff sowie eines Dispergierhilfsmittels, das aus organischen Polyelektrolyten und quartären Ammoniumbasen ausgewählt ist, einer Elektrophorese unterzieht. Mit diesem Verfahren lassen sich Grünkörper herstellen, die über eine extrem homogene Verteilung der Sinteradditive im Siliciumcarbid verfügen.
[EN] Producing silicon carbide (SiC) green prods. (I) comprises electrophoresis of a suspension of alpha-SiC particles (II) in a polar aprotic solvent (III) in the presence of finely-divided B4C, finely-divided carbon and an organic polyelectrolyte and/or quat. ammonium base as dispersant (IV). (III) are 1-6C (pref. 1-4C) aliphatic alcohols and/or 3-6C (pref. 3-4C) aliphatic ketones. The suspension contains 5-80 (pref. 20-70) wt.% (II) with mean particle size 2 nm-2 microns, pref. 0.01-1.5 microns. The B4C. has particle size not above 1.5 (pref. not above 1) micron and is present in amts. of 0.1-2 (pref. 0.2-1) wt.%, and the carbon has particle size not above 0.5 (pref. not above 0.1) micron and is present in amts. of 0.5-3 (pref. 1-2) wt.% (w.r.t. II). (IV) is a basic (esp. N-contg.) polyelectrolyte, pref. polyethylene-imine, polyalkanolamine and/or polyvinyl-amine, or a base of formula R4N+OH- (with R=1-6C, pref. 1-4C, alkyl), in amts. of 0.1-2 (pref. 0.5-1.5) wt.% w.r.t. total solids content of suspension. Water is added, pref. in amts. of 0.01-5 (esp. 0.05-2) wt.% w.r.t. total solids. Electrophoresis is carried out at 500-100,000 (esp. 1000-50,000) V/m until a deposit of thickness 0.01-5 (pref. 0.1-3) cm is obtd. USE/ADVANTAGE - For prodn. of sintered prods., esp. ceramic components, pref. by unpressurised sintering (claimed). The process enables a very homogeneous distribution of additives (B4C. and carbon) in the SiC, resulting in a very high sinter density and final prods. with very good mechanical properties and a low fault rate; high rates of prodn. are possible without loss of homogeneity, and the green density can be controlled by varying the water content of the suspension. |
| 56 |
Cited documents identified in the search |
CT |
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| 56 |
Cited documents indicated by the applicant |
CT |
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| 56 |
Cited non-patent literature identified in the search |
CTNP |
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| 56 |
Cited non-patent literature indicated by the applicant |
CTNP |
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Citing documents |
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Determine documents
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Sequence listings |
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Search file IPC |
ICP |
C04B 35/569
C25B 1/00
C25B 7/00
|
