Patent US5663590A successfully refreshed from Google Patents.
Patent EP0261057A2 successfully refreshed from Google Patents.
EP0261057A2
Expired / Lapsed
EP
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Dense skin ceramic structure and method of making the same
Assignee: Lanxide Technology Co LP
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Filing: 1987-09-03
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Granted: —
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Expires: 2007-09-03
Abstract
Abstract The disclosure concerns self-supporting ceramic structures, including ceramic composite structures embedding a filler, and methods of making them. The ceramic structures comprise a polycrystlline material made by oxidation of a body of molten parent metal with an oxidant. The polycrystalline material has a first region substrate surmounted by a terminal region stratum which is integral with the first region. The terminal region stratum which is harder and of denser, finer crystalline structure than the first region substrate and is formed in a reaction stage subsequent to the reaction stage in which the first region of polycrystalline material is formed. Growth of the first stage is attained by by attenuating or interrupting the transport of molten parent metal to the first region under conditions which nonetheless leave or maintain therein enough oxidizable molten parent metal to form the polycrystalline material of the terminal region.
Inventors
- 👤 Stanley J. Luszcz
- 👤 Harry R. Zwicker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 10:16
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/71; C04B35/74; C04B35/622; C04B35/64; C04B35/65; C04B35/652; C22; C22C; C22C29/00; C22C29/12
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
235 words
A method for producing a self supporting ceramic structure comprising a polycrystalline material comprised of a first region and a terminal region integral with said first region but differing therefrom in one or both of composition and microstructure, the method comprising the steps of: (a) heating said parent metal to a temperature range above its melting point but below the melting point of the oxidation reaction product to form a body of molten parent metal; and (b) within said temperature range, (i) reacting said body of molten parent metal with an oxidant to form said oxidation reaction product, (ii) initially maintaining at least a portion of said oxidation reaction product in contact with and between said body of molten parent metal and said oxidant to progressively transport molten parent metal from said body through the oxidation reaction product and towards the oxidant, so that oxidation reaction product continues to form at the interface between the oxidant and previously formed oxidation reaction product, thereby forming a progressively thicker first region of oxidation reaction product initially containing interconnected parent metal; c) attenuating said transport of molten parent metal from said body, and d) after step (c), continuing said reacting within said temperature range for a time sufficient to transport said interconnected molten parent metal from said first region toward a surface of said first region to form oxidation reaction product on said surface as said terminal region.
Claim 2
Independent Claim
235 words
A method for producing a self supporting ceramic structure comprising a polycrystalline material comprised of a first region and a terminal region integral with said first region but differing therefrom in one or both of composition and microstructure, the method comprising the steps of: (a) heating said parent metal to a temperature range above its melting point but below the melting point of the oxidation reaction product to form a body of molten parent metal; and (b) within said temperature range, (i) reacting said body of molten parent metal with an oxidant to form said oxidation reaction product, (ii) initially maintaining at least a portion of said oxidation reaction product in contact with and between said body of molten parent metal and said oxidant to progressively transport molten parent metal from said body through the oxidation reaction product and towards the oxidant, so that oxidation reaction product continues to form at the interface between the oxidant and previously formed oxidation reaction product, thereby forming a progressively thicker first region of oxidation reaction product initially containing interconnected parent metal; c) attenuating said transport of molten parent metal from said body, and d) after step (c), continuing said reacting within said temperature range for a time sufficient to transport said interconnected molten parent metal from said first region toward a surface of said first region to form oxidation reaction product on said surface as said terminal region.
Claim 3
Dependent Claim
23 words
The method of claim 1 including continuing said reacting at least to the point of exhaustion of said body of molten parent metal.
Claim 4
Dependent Claim
62 words
The method of claim 1 including orienting a mass of filler and one or both of said parent metal and said resultant polycrystalline material relative to each other so that said polycrystalline material grows towards and into said filler whereby at least part of said filler is embedded by said polycrystalline materials to provide said ceramic structure as a ceramic composite body.
Claim 5
Dependent Claim
78 words
The method of claim 1 including forming at least a part of said first region in a first reacting stage and thereafter orienting a mass filler and said first region relative to each other so that upon forming said terminal region in a second reacting stage, said terminal region grows towards and into said filler whereby at least a portion of said filler is embedded by said terminal region and said ceramic structure comprises a ceramic composite structure.
Claim 6
Dependent Claim
107 words
The method of claim 1 including providing said ceramic structure as a ceramic composite structure by (1) orienting said parent metal and a mass of first filler relative to each other and, in a first reacting stage, forming said first region towards and into said first filler to embed at least a part of said first filler therein, and (2) thereafter orienting the first region polycrystalline material obtained from step (1) and a mass second filler relative to each other and, in a second reacting stage, forming said terminal region towards and into said second filler to embed at least a part of said second filler therein.
Claim 7
Dependent Claim
15 words
The method of claim 9 wherein said first filler is different from said second filler.
Claim 8
Independent Claim
21 words
The method of any one of claims 1, 2, 3, 4, 5, or 6 wherein said oxidant is a vapor-phase oxidant.
Claim 9
Dependent Claim
42 words
The method of claim 7 wherein said vapor-phase oxidant is an oxygen-containing gas, said parent metal is an aluminum parent metal, said polycrystalline material is comprised of alpha-alumina, and including using at least one suitable dopant in conjunction with said parent metal.
Claim 10
Dependent Claim
21 words
The method of claim 8 wherein said oxidant is air and said temperature range is from about 850°C to about 1450°C.
Claim 11
Independent Claim
26 words
The method of any one of claims 1, 2, 3, 4, 5, or 6 wherein said terminal region has a finer microstructure than said first region.
Claim 12
Independent Claim
43 words
The method of any one of claims 1, 2, 3, 4, 5, or 6 including interposing a barrier means in at least a portion of the path of formation of said polycrystalline material to thereby limit and define the extent of such formation.
Claim 13
Dependent Claim
68 words
A self-supporting ceramic structure comprising a polycrystalline material having a first region substrate surmounted by a terminal region stratum which is integral with said first region but differs therefrom in one or both of composition and microstructure, said polycrystalline material comprising an oxidation reaction product of interconnected crystallites formed at a temperature below the melting point of said oxidation reaction product upon oxidation of a molten metal precursor.
Claim 14
Dependent Claim
68 words
A self-supporting ceramic structure comprising a polycrystalline material having a first region substrate surmounted by a terminal region stratum which is integral with said first region but differs therefrom in one or both of composition and microstructure, said polycrystalline material comprising an oxidation reaction product of interconnected crystallites formed at a temperature below the melting point of said oxidation reaction product upon oxidation of a molten metal precursor.
Claim 15
Dependent Claim
16 words
The ceramic structure of claim 12 wherein said first region contains one or more metallic constituents.
Claim 16
Dependent Claim
23 words
The ceramic structure of claim 12 wherein said first region contains said one or more metallic constituents in the form of isolated inclusions.
Claim 17
Dependent Claim
21 words
The ceramic structure of claim 12 wherein said terminal region stratum has a higher Rockwell hardness than said first region substrate.
Claim 18
Dependent Claim
20 words
The ceramic structure of claim 12 wherein said terminal region stratum has a finer crystallite microstructure than said first region.
Claim 19
Dependent Claim
27 words
The ceramic structure of any one of claims 12, 13, 14, 15, or 16 wherein at least one of said first and terminal regions embeds a filler.
Claim 20
Dependent Claim
23 words
The ceramic structure of any one of claims 12, 13, 14, 15, or 16 wherein said polycrystalline material is comprised of alpha alumina.
Claim 21
Dependent Claim
15 words
The ceramic structure of claim 18 wherein said one or more metallic constituents comprises aluminum.
References Cited (Backward Citations)
No citation records indexed.
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