EP0306034A2
Expired / Lapsed
EP
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Method and composition for forming superconducting ceramics and other ceramic materials with reduced electrical resistivity and electrically conductive metal-clad products therefrom
Assignee: WR Grace and Co Conn
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Filing: 1988-09-02
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Granted: —
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Expires: 2008-09-02
Abstract
Abstract A method for forming superconducting ceramics and other ceramic materials with reduced electrical resistivity which have metal cladding is disclosed using certain blends of particles of the ceramic materials (or their precursors) with polymers and plasticizers and blends of certain conductive metal particles with polymers and plasticizers. In accordance with the invention the blends can be shaped by conventional means, the plasticizer can be removed by extraction and/or volatilization, the polymer can be volatilized, and the ceramic particles can be sintered to yield the desired product.
Inventors
- 👤 Christian Bent Lundsager
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 15:44
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/45; C04B35/4504; C04B35/4508; B; B32; B32B; B32B18/00; H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; H10N60/0801; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/341; C04B2237/343; C04B2237/50; C04B2237/68; C04B2237/70; C04B2237/704; C04B2237/76; C04B2237/765
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
230 words
A method for forming shaped solid products with reduced electrical resistivity comprising the steps of: (a) providing a substantially uniform plastic blend comprising at least about 60 weight percent of particles of ceramic materials which exhibit reduced electrical resistivity, particles of precursors of said ceramic materials, or both; from about 2 to about 10 weight percent total of at least one polymer which has a molecular weight of at least about 100,000; and about 30 weight percent or less of a plasticizer for said polymer; wherein the polymer component and the plasticizer component are unreactive with the particles of the ceramic component such that the particles remain substantially unchanged during blending; and wherein the polymer, at least in the presence of the plasticizer, is one that can be made fluid during processing such that it can be blended with the ceramic and plasticizer components, and is one that can be solidified after blending; (b) providing a blend comprising a polymer, a plasticizer, and particles of a conductive metal which is capable of retaining its conductivity without volatilizing during firing; (c) firmly bonding and shaping the blends to form a composition of the shape desired for the shaped solid products; (d) removing the plasticizer by extraction or volatilization; (e) heating the composition to volatilize the polymer; and (f) firing the composition to at least about 900°C to sinter the ceramic components.
Claim 2
Independent Claim
230 words
A method for forming shaped solid products with reduced electrical resistivity comprising the steps of: (a) providing a substantially uniform plastic blend comprising at least about 60 weight percent of particles of ceramic materials which exhibit reduced electrical resistivity, particles of precursors of said ceramic materials, or both; from about 2 to about 10 weight percent total of at least one polymer which has a molecular weight of at least about 100,000; and about 30 weight percent or less of a plasticizer for said polymer; wherein the polymer component and the plasticizer component are unreactive with the particles of the ceramic component such that the particles remain substantially unchanged during blending; and wherein the polymer, at least in the presence of the plasticizer, is one that can be made fluid during processing such that it can be blended with the ceramic and plasticizer components, and is one that can be solidified after blending; (b) providing a blend comprising a polymer, a plasticizer, and particles of a conductive metal which is capable of retaining its conductivity without volatilizing during firing; (c) firmly bonding and shaping the blends to form a composition of the shape desired for the shaped solid products; (d) removing the plasticizer by extraction or volatilization; (e) heating the composition to volatilize the polymer; and (f) firing the composition to at least about 900°C to sinter the ceramic components.
Claim 3
Dependent Claim
22 words
The method of Claim 1 wherein the plasticizer is at least partially extracted with a solvent after shaping and prior to firing.
Claim 4
Dependent Claim
29 words
The method of Claim 1 wherein the polymer is thermoplastic such that it can be made fluid and solidified by respectively raising and lowering the temperature of the polymer.
Claim 5
Dependent Claim
11 words
The method of Claim 1 wherein the polymer is a polyolefin.
Claim 6
Dependent Claim
54 words
The method of Claim 1 wherein the polymer is selected from the group consisting of polyethylene, polypropylene, and polystyrene; and wherein the plasticizer is selected from the group consisting of mineral oil, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, glycerol monoacetate, trimethylene glycol, tetramethylene glycol, 2,3-butylene glycol, triethyl phosphate, polyvinyl alcohol, and polyvinyl pyrrolidone.
Claim 7
Dependent Claim
11 words
The method of Claim 1 wherein the ceramic material is superconductive.
Claim 8
Dependent Claim
224 words
An integral solid comprising a first portion which has reduced electrical resistivity and a second portion which is a conductive metal formed by: (a) firmly bonding a first composition to a second composition, said first composition being a substantially uniform blend comprising at least about 60 weight percent of ceramic materials which exhibit reduced electrical resistivity, particles of precursors of said ceramic material, or both; from about 2 to about 10 weight percent total of at least one polymer which has a molecular weight of at least about 100,000; and from about 2 to about 30 weight percent of a plasticizer for said polymer; wherein the polymer component and the plasticizer component are unreactive with the particles of the ceramic component such that the particles remain substantially unchanged during blending; and wherein the polymer, at least in the presence of the plasticizer is one that can be made fluid for blending and is one that can be solidified after blending; and said second composition being a blend comprising a polymer, a plasticizer, and particles of a conductive metal; and (b) firing the bonded blends such that the temperature first attains a range to volatilize the non-ceramic components and then is raised to a temperature of at least about 900°C, said temperature being sufficient to sinter the ceramic particles or their precursors without volatilizing them.
Claim 9
Dependent Claim
224 words
An integral solid comprising a first portion which has reduced electrical resistivity and a second portion which is a conductive metal formed by: (a) firmly bonding a first composition to a second composition, said first composition being a substantially uniform blend comprising at least about 60 weight percent of ceramic materials which exhibit reduced electrical resistivity, particles of precursors of said ceramic material, or both; from about 2 to about 10 weight percent total of at least one polymer which has a molecular weight of at least about 100,000; and from about 2 to about 30 weight percent of a plasticizer for said polymer; wherein the polymer component and the plasticizer component are unreactive with the particles of the ceramic component such that the particles remain substantially unchanged during blending; and wherein the polymer, at least in the presence of the plasticizer is one that can be made fluid for blending and is one that can be solidified after blending; and said second composition being a blend comprising a polymer, a plasticizer, and particles of a conductive metal; and (b) firing the bonded blends such that the temperature first attains a range to volatilize the non-ceramic components and then is raised to a temperature of at least about 900°C, said temperature being sufficient to sinter the ceramic particles or their precursors without volatilizing them.
Claim 10
Dependent Claim
20 words
The integral solid of Claim 7 wherein, during its formation, the blend is bonded to the second composition by coextrusion.
Claim 11
Dependent Claim
21 words
The integral solid of Claim 7 wherein, during its formation, the blend is bonded to the second composition by heat sealing.
Claim 12
Dependent Claim
38 words
The integral solid of Claim 7 comprising a composite bar having a first portion which is a cylindrical core of superconducting material and a second portion which is a metal cladding which provides electrical conductivity at room temperature.
Claim 13
Dependent Claim
23 words
The integral ceramic solid of Claim 7 comprising a sheet of ceramic having reduced electrical resistivity layered between two sheets of metal cladding.
Claim 14
Dependent Claim
15 words
The integral solid of Claim 7 additionally comprising at least one portion of insulating ceramic.
Claim 15
Dependent Claim
12 words
The integral solid of Claim 7 wherein the conductive metal is silver.
Claim 16
Dependent Claim
26 words
The integral solid of Claim 7 wherein the ceramic material is superconducting metal oxide powder of yttrium, barium, and copper in an atomic ratio of 1:2:3.
References Cited (Backward Citations)
No citation records indexed.
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