EP0009352A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Sealing of ceramic and cermet parts, sealing material therefor and ceramic seal obtained
Assignee: EMI Group Ltd
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Filing: 1979-09-04
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Granted: —
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Expires: 1999-09-04
Abstract
Abstract The invention provides a particulate sealing material for use in preparing hermetic seals between ceramic and cermet members, which material comprises at least 70 wt. % refractory oxide and minor quantities of non-vitreous additive comprising Si0<sub>2</sub>, MgO and B<sub>2</sub>O<sub>3</sub>. This particulate sealing material is conveniently pressed into the form of a coherent element shaped to suit the particular sealing operation concerned, e.g. the sealing of an open end of a ceramic arc tube to a cermet closure therefor. The invention also provides a method of sealing a ceramic component to a cermet member by interposing said sealing material between the opposed faces of the component and member and applying heat and pressure to sinter the sealing material and achieve a seal between the component and member.
Inventors
- 👤 Peter Dr. Hing
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 08:59
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/36; C; C04; C04B; C04B37/00; C04B37/02; C04B37/023; C04B37/025; H01J9/00; H01J9/24; H01J9/245; H01J9/247; H01J9/26; C04B2237/00; C04B2237/02; C04B2237/04; C04B2237/06; C04B2237/062; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/40; C04B2237/401; C04B2237/50; C04B2237/76; C04B2237/765; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/252; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
85 words
_ A particulate sealing material for use in preparing hermetic seals between ceramic and cermet members, which material comprises (a) at least 70 wt.% (e.g. 70 to 97 wt.% and preferably at most 93 wt.%) of refractory oxide which preferably comprises alumina, and (b) a minor quantity of non-vitreous additive which comprises Si0 2 , MgO and B 2 0 3 and preferably contains 1-10% MgO, 2-20% SiO 2 and up to 2% B 2 0 3 based on the weight of the sealing material.
Claim 2
Dependent Claim
85 words
_ A particulate sealing material for use in preparing hermetic seals between ceramic and cermet members, which material comprises (a) at least 70 wt.% (e.g. 70 to 97 wt.% and preferably at most 93 wt.%) of refractory oxide which preferably comprises alumina, and (b) a minor quantity of non-vitreous additive which comprises Si0 2 , MgO and B 2 0 3 and preferably contains 1-10% MgO, 2-20% SiO 2 and up to 2% B 2 0 3 based on the weight of the sealing material.
Claim 3
Dependent Claim
17 words
A material according to claim 1 comprising refractory oxide granules coated with finer particles of the additive.
Claim 4
Dependent Claim
17 words
A sealing material according to claim 1 or 2 in the form of a snaped pressed element.
Claim 5
Independent Claim
60 words
A method of sealing a ceramic component to a cermet member in which an intermediate sealing material according to any preceding claim is interposed between the component and the member, and the intermediate sealing material and the opposed surfaces of the component and member are heated while compressed together to sinter the material and achieve a seal between the surfaces.
Claim 6
Dependent Claim
20 words
A method according to claim 4 wherein at least one of the ceramic component and the cermet member contains alumina.
Claim 7
Dependent Claim
37 words
A method according to claim 4 or 5 wherein the surfaces and intermediate sealing material are heated to from 600°C to 15000C and compressed at a pressure of from 50 Kg/cm 2 to 300 Kg/cm 2 .
Claim 8
Independent Claim
47 words
A method according to any of claims 4 to 6 in which the ceramic component is an arc tube and the cermet member is a closure for an end of the tube, preferably the second end to be closed of an arc tube containing volatile fill constituents.
Claim 9
Dependent Claim
117 words
An integral composite body including a ceramic component and a cermet member at least one of which is preferably alumina-containing,the component and member having opposed faces sealed together by an interposed sintered composition which comprises (a)at least 70% and preferably at most 93% by weight of refractory oxide which preferably comprises alumina and (b) minor quantities of non-vitreous silicon, magnesium and boron oxides, the interposed sintered composition having a microstructure characterised by flattened refractory oxide-rich grains generally aligned parallel to the said faces and substantially surrounded and interconnected by non-vitreous material which is rich in silicon, magnesium, and boron oxides and forms layers thinner than the grains and also generally aligned generally parallel to the said faces.
Claim 10
Dependent Claim
117 words
An integral composite body including a ceramic component and a cermet member at least one of which is preferably alumina-containing,the component and member having opposed faces sealed together by an interposed sintered composition which comprises (a)at least 70% and preferably at most 93% by weight of refractory oxide which preferably comprises alumina and (b) minor quantities of non-vitreous silicon, magnesium and boron oxides, the interposed sintered composition having a microstructure characterised by flattened refractory oxide-rich grains generally aligned parallel to the said faces and substantially surrounded and interconnected by non-vitreous material which is rich in silicon, magnesium, and boron oxides and forms layers thinner than the grains and also generally aligned generally parallel to the said faces.
Claim 11
Dependent Claim
30 words
A body according to claim 8 wherein the refractory oxide of the interposed sintered composition is of substantially smaller grain size than that of the ceramic component and cermet member.
Claim 12
Dependent Claim
33 words
A body according to claim 8 or 9 wherein the ceramic component is an end of an arc tube and the cermet member is a closure for the said end of the tube.
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DE2734015A1
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