US 4,847,025 AGranted

Method of making ceramic articles having channels therein and articles made thereby

AssigneeLanxide Technology Company, LP

InventorsDanny R. White, Michael K. Aghajanian

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Abstract

A method is provided for producing a self-supporting ceramic body comprising a polycrystalline material comprised of the oxidation reaction product of a parent metal and having therein one or more channels which inversely replicate the geometry of a configured fugitive metal. The method includes providing an assembly of the configured fugitive metal and the parent metal, optionally including a bed of permeable filler, and heating the assembly to form a body of molten parent metal. The molten parent metal is oxidized under selected conditions to grow the polycrystalline material to engulf the configured fugitive metal (and to infiltrate the filler, if the filler is present) and to cause the fugitive metal to disperse into the engulfing polycrystalline material thereby leaving behind as the one or more channels the space formerly occupied by the configured fugitive metal. The method provides self-supporting ceramic bodies having therein one or more channels inversely replicating the shape of the configured fugitive metal.

Claims20

Dependent claims

A method for producing a self-supporting ceramic body having therein at least one channel inversely replicating the geometry of a configured fugitive metal, said ceramic body being obtained by oxidation of a parent metal to form a polycrystalline material comprising an oxidation reaction product of said parent metal with an oxidant, the method comprising the steps of:

(a) positioning said configured fugitive metal adjacent to said parent metal such that formation of oxidation reaction product of the parent metal will engulf at least a portion of said configured fugitive metal;
(b) heating said parent metal to a temperature region above its melting point but below the melting point of said oxidation reaction product to form a body of molten parent metal and, at said temperature region, reacting the molten parent metal with said oxidant to form said oxidation reaction product, and maintaining at least a portion of said oxidation reaction product in contact with and between said body of molten metal and said oxidant, to progressively draw molten parent metal through the oxidation reaction product towards said oxidant and said configured fugitive metal to form fresh oxidation reaction product at an interface between said oxidant and previously formed oxidation reaction product;
(c) continuing said reacting for a time sufficient to engulf at least a portion of said configured fugitive metal within said polycrystalline material, whereby said fugitive metal substantially maintains its original shape until it is contacted by said oxidation reaction product, whereupon said fugitive metal becomes dispersed within said polycrystalline material and at least one channel which inversely replicates the geometry of said engulfed portion of said configured fugitive metal is substantially concurrently formed;
and
(d) recovering said ceramic body.

2 more elements

A method for producing a self-supporting ceramic composite body having therein at least one channel inversely replicating the geometry of a configured fugitive metal, said ceramic composite body comprising a ceramic matrix obtained by oxidation of a parent metal to form a polycrystalline material and a filler material infiltrated by said ceramic matrix, the method comprising the steps of:

(a) positioning said configured fugitive metal, supported by a mass of filler material, adjacent to a parent metal such that formation of oxidation reaction product of the parent metal will infiltrate said filler and engulf at least a portion of said configured fugitive metal, said filler material being permeable to growth therethrough of said oxidation reaction product;
(b) heating said parent metal to a temperature region above its melting point but below the melting point of said oxidation reaction product to form a body of molten parent metal and, at said temperature region, reacting the molten parent metal with an oxidant to form said oxidation reaction product, and maintaining at least a portion of said oxidation reaction product in contact with and between said body of molten metal and said oxidant to progressively draw molten parent metal through the oxidation reaction product towards said oxidant and said configured fugitive metal to form fresh oxidation reaction product at an interface between said oxidant and previously formed oxidation reaction product;
(c) continuing said reacting for a time sufficient to engulf at least a portion of said configured fugitive metal within said polycrystalline material, whereby said fugitive metal substantially maintains its original shape until it is contacted by said oxidation reaction product, whereby said fugitive metal becomes dispersed within said polycrystalline material, and at least one channel which inversely replicates the geometry of said engulfed portion of said configured fugitive metal is substantially concurrently formed;
and
(d) separating the resulting ceramic composite body from any excess filler.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/907,924Filed 16 Sep 1986
Granted: 11 Jul 1989
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B28B 3/025
Wherein a ram exerts pressure on the material in a moulding space; Ram heads of special form: hot pressing, e.g. of ceramic materials
B28B 1/00
Producing shaped prefabricated articles from the material
B28B 7/342
Moulds, cores, or mandrels of special material, e.g. destructible materials: which are at least partially destroyed, e.g. broken, molten, before…
C04B 35/652
Reaction sintering of free metal- or free silicon-containing compositions: directional oxidation or solidification, e.g. Lanxide process