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1. (WO1991005747) METHOD OF HEAT-TREATING UNSTABLE CERAMICS BY MICROWAVE HEATING AND SUSCEPTORS USED THEREFOR
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1991/005747 International Application No.: PCT/CA1990/000358
Publication Date: 02.05.1991 International Filing Date: 19.10.1990
Chapter 2 Demand Filed: 08.05.1991
IPC:
B01J 19/12 (2006.01) ,B30B 11/00 (2006.01) ,C04B 35/64 (2006.01) ,C04B 35/645 (2006.01)
B PERFORMING OPERATIONS; TRANSPORTING
01
PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
J
CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS, COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
19
Chemical, physical, or physico-chemical processes in general; Their relevant apparatus
08
Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
12
employing electromagnetic waves
B PERFORMING OPERATIONS; TRANSPORTING
30
PRESSES
B
PRESSES IN GENERAL; PRESSES NOT OTHERWISE PROVIDED FOR
11
Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
C CHEMISTRY; METALLURGY
04
CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
B
LIME; MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
35
Shaped ceramic products characterised by their composition; Ceramic compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
622
Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
64
Burning or sintering processes
C CHEMISTRY; METALLURGY
04
CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
B
LIME; MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
35
Shaped ceramic products characterised by their composition; Ceramic compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
622
Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
64
Burning or sintering processes
645
Pressure sintering
Applicants:
ALCAN INTERNATIONAL LIMITED [CA/CA]; 1188 Sherbrooke Street, West Montreal, Quebec H3A 3G2, CA (AllExceptUS)
APTÉ, Prasad, Shrikrishna [CA/CA]; CA (UsOnly)
KIMBER, Robert, Murray [CA/CA]; CA (UsOnly)
PATTERSON, Mark, Christopher, Lawrence [CA/CA]; CA (UsOnly)
ROY, Raymond, Yves [CA/CA]; CA (UsOnly)
MITCHELL, David, Nelson [CA/CA]; CA (UsOnly)
Inventors:
APTÉ, Prasad, Shrikrishna; CA
KIMBER, Robert, Murray; CA
PATTERSON, Mark, Christopher, Lawrence; CA
ROY, Raymond, Yves; CA
MITCHELL, David, Nelson; CA
Agent:
GALE, Edwin, J. ; Kirby, Eades, Gale, Baker & Potvin Box 3432 Station D Ottawa, Ontario K1P 6N9, CA
Priority Data:
2,001,06219.10.1989CA
Title (EN) METHOD OF HEAT-TREATING UNSTABLE CERAMICS BY MICROWAVE HEATING AND SUSCEPTORS USED THEREFOR
(FR) PROCEDE DE TRAITEMENT THERMIQUE DE MATERIAUX CERAMIQUES INSTABLES PAR CHAUFFAGE AUX MICRO-ONDES ET ABSORBEURS DE MICRO-ONDES UTILISES DANS CE PROCEDE.
Abstract:
(EN) A method of sintering thermally unstable (usually non-oxyde) ceramics by microwave heating. In the method, a body of the ceramic is at least partially surrounded with a protective bed of particulate material and then the body and the bed (34) are subjected to microwave irradiation to cause heating and sintering of the body. In order to allow the method to be carried out in an oxygen-containing gas such as air and at low pressure, the bed contains effective amounts of: (a) a microwave susceptor, if the unstable ceramic is not already a susceptor, (b) a protective material capable of generating a localized atmosphere which reduces decomposition and/or oxidation of the unstable ceramic, (c) an oxygen getter and (d) a material of sufficiently good thermal conductivity to prevent excessive localized heating in the bed. The process can be combined with a hot isostatic pressing step carried out simultaneously or subsequently. The invention also relates to the bed of particulate material used in the method and to a process for joining bodies of unstable ceramics by microwave irradiation using the protective bed.
(FR) L'invention se rapporte à un procédé de frittage de matériaux céramiques thermiquement instables (généralement non oxyde) par chauffage aux micro-ondes. Dans ce procédé, un corps du matériaux céramique est au moins partiellement entouré d'un lit protecteur de matériau particulaire, puis le corps et le lit (34) sont soumis à un rayonnement de micro-ondes destiné à assurer le chauffage et le frittage du corps. Pour permettre la réalisation du procédé dans un gaz contenant de l'oxygène, tel que de l'air, et à basse pression, le lit contient des quantités efficaces de: (A) un absorbeur de micro-ondes, lorsque le matériau céramique instable ne l'est pas déjà; (b) un matériau protecteur capable de produire une atmosphère localisée qui réduit la décomposition et/ou l'oxydation du matériau céramique instable; (c) un getter d'oxygène; et (d) un matériau de conductivité thermique suffisamment bonne pour empêcher un chauffage localisé excessif dans le lit. Ce procédé peut être combiné avec une étape de pressage isostatique à chaud effectuée simultanément ou ultérieurement. L'invention se rapporte égallement au lit de matériau particulaire utilisé dans le procédé et à un procédé permettant d'assembler des corps de matériau céramique instable par rayonnement de micro-ondes en utilisant le lit protecteur.
Designated States: AU, JP, KR, US
European Patent Office (AT, BE, CH, DE, DK, ES, FR, GB, GR, IT, LU, NL, SE)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
EP0495850JPH05500940AU1990065400