Ceramic composite and methods of making the same

Claim 2

A refractory component for use in contact with molten metal comprising: a) a ceramic matrix which is three-dimensionally interconnected, said ceramic matrix comprising an oxidation reaction product of a parent metal comprising aluminum, said ceramic matrix containing less than about 0.5% by weight residual aluminum parent metal; b) said ceramic matrix embedding at least one filler material, thereby forming a ceramic composite body, said ceramic composite body having a porosity which is interconnected, said interconnected porosity comprising openings having a mean diameter of less than about 6 microns.

Claim 3

The refractory component of claim 1, wherein said refractory component has a modulus of rupture of about 3500-6500 psi at about 1400° C. in a nitrogen atmosphere.

Claim 4

The refractory component of claim 1, wherein said refractory component has a thermal shock resistance of about 60° C./in. 1/2 .

Claim 5

The refractory component of claim 1, wherein said refractory component has a volume stability of not greater than about 0.15%.

Claim 6

The refractory component of claim 1, wherein said refractory component has a corrosion resistance of not greater than about 0.04 inch.

Claim 7

The refractory component of claim 1, wherein said filler material comprises at least one metal oxide, boride or carbide of a metal selected from the group consisting of aluminum, cerium, hafnium, lanthanum, silicon, neodymium, praseodymium, samarium, scandium, thorium, uranium, titanium, yttrium, and zirconium.

Claim 8

The refractory component of claim 1, wherein said oxidation reaction product has substantially clean grain boundaries.

Claim 9

The refractory component of claim 7, wherein said substantially clean grain boundaries are substantially devoid of any siliceous phase.

Claim 10

The refractory component of claim 1, wherein said refractory component is characterized as at least one article selected from the group consisting of a slide gate, a sub-entry nozzle and a ladle shroud.

Claim 11

A refractory component for use in contact with molten metal formed by a method comprising: a) positioning a parent metal, comprising an aluminum alloy containing at least about 1% by weight zinc, adjacent to a filler material having at least one defined surface boundary and orienting said parent metal and said filler material relative to each other so that formation of an oxidation reaction product of the parent metal with an oxidant will occur into said filler material and in a direction towards said defined surface boundary; b) heating said parent metal to a first temperature above its melting point but below the melting point of said oxidation reaction product to form a body of molten parent metal and reacting the molten parent metal with said oxidant at said first temperature to form said oxidation reaction product, and at said first temperature maintaining at least a portion of said oxidation reaction product in contact with and extending between said body of molten metal and said oxidant, to draw molten metal through the oxidation reaction product towards the oxidant and towards and into the adjacent filler material so that fresh oxidation reaction product continues to form within the filler material at an interface between the oxidant and previously formed oxidation reaction product, and continuing said reaction for a time sufficient to infiltrate said filler material to said defined surface boundary, with said ceramic matrix, said ceramic matrix containing at least some residual non-oxidized metallic constituents of said parent metal; and c) heating the resulting infiltrated filler material of step (b) in at least one environment selected from the group consisting of an oxygen-containing atmosphere, an inert atmosphere and a vacuum to a second temperature above the first temperature but below the melting point of the oxidation reaction product to remove or oxidize sufficient residual non-oxidized aluminum parent metal without substantial formation of oxidation reaction product beyond said defined surface boundary such that said ceramic matrix contains less than about 0.5% by weight said residual aluminum parent metal, thereby providing said refractory component.

Claim 12

A refractory component for use in contact with molten metal formed by a method comprising: a) positioning a parent metal, comprising an aluminum alloy containing at least about 1% by weight zinc, adjacent to a filler material having at least one defined surface boundary and orienting said parent metal and said filler material relative to each other so that formation of an oxidation reaction product of the parent metal with an oxidant will occur into said filler material and in a direction towards said defined surface boundary; b) heating said parent metal to a first temperature above its melting point but below the melting point of said oxidation reaction product to form a body of molten parent metal and reacting the molten parent metal with said oxidant at said first temperature to form said oxidation reaction product, and at said first temperature maintaining at least a portion of said oxidation reaction product in contact with and extending between said body of molten metal and said oxidant, to draw molten metal through the oxidation reaction product towards the oxidant and towards and into the adjacent filler material so that fresh oxidation reaction product continues to form within the filler material at an interface between the oxidant and previously formed oxidation reaction product, and continuing said reaction for a time sufficient to infiltrate said filler material to said defined surface boundary, with said ceramic matrix, said ceramic matrix containing at least some residual non-oxidized metallic constituents of said parent metal; and c) heating the resulting infiltrated filler material of step (b) in at least one environment selected from the group consisting of an oxygen-containing atmosphere, an inert atmosphere and a vacuum to a second temperature above the first temperature but below the melting point of the oxidation reaction product to remove or oxidize sufficient residual non-oxidized aluminum parent metal without substantial formation of oxidation reaction product beyond said defined surface boundary such that said ceramic matrix contains less than about 0.5% by weight said residual aluminum parent metal, thereby providing said refractory component.

Claim 13

The refractory component of claim 1, wherein said component comprises a slide gate valve refractory having a slide gate structure defining at least one slide gate aperture and having a generally planar surface for slidably contacting a ladle means having a ladle aperture and containing molten metal in order to permit and regulate the flow of the molten metal from the ladle means through the ladle aperture and the slide gate aperture.

Claim 14

The component of claim 11, wherein said filler material further comprises from about 3% by weight to about 10% by weight silica.

Claim 15

The component of claim 10, wherein said filler material further comprises alumina having having a mesh size of from about 5 to about 500.

Claim 16

The component of claim 11, wherein at least a portion of said interconnected porosity is accessible from at least one surface of said ceramic matrix.

Claim 17

A refractory component for use in contact with molten metal comprising: a) a ceramic matrix which is three-dimensionally interconnected, said ceramic matrix comprising an oxidation reaction product of a parent metal comprising aluminum, said ceramic matrix containing less than about 0.5% by weight residual aluminum parent metal; b) said ceramic matrix embedding at least one filler material, said filler material comprising at least one metal oxide, boride or carbide of a metal selected from the group consisting of aluminum, cerium, hafnium, lanthanum, silicon, neodymium, praseodymium, samarium, scandium, thorium, uranium, titanium, yttrium, and zirconium, thereby forming a ceramic composite body, said ceramic composite body (1) having a porosity which is interconnected, said interconnected porosity comprising openings having a mean diameter of less than about 6 microns; (2) having a modulus of rupture from about 3500-6500 psi at about 1400° C. in a nitrogen atmosphere; (3) having a thermal shock resistance parameter of about 60° C./in.1/2; (4) having a volume stability of not greater than about 0.15%; and (5) having a corrosion resistance of not greater than about 0.04 inch.

Claim 18

A refractory component for use in contact with molten metal comprising: a) a ceramic matrix which is three-dimensionally interconnected, said ceramic matrix comprising an oxidation reaction product of a parent metal comprising aluminum, said ceramic matrix containing less than about 0.5% by weight residual aluminum parent metal; b) said ceramic matrix embedding at least one filler material, said filler material comprising at least one metal oxide, boride or carbide of a metal selected from the group consisting of aluminum, cerium, hafnium, lanthanum, silicon, neodymium, praseodymium, samarium, scandium, thorium, uranium, titanium, yttrium, and zirconium, thereby forming a ceramic composite body, said ceramic composite body (1) having a porosity which is interconnected, said interconnected porosity comprising openings having a mean diameter of less than about 6 microns; (2) having a modulus of rupture from about 3500-6500 psi at about 1400° C. in a nitrogen atmosphere; (3) having a thermal shock resistance parameter of about 60° C./in.1/2; (4) having a volume stability of not greater than about 0.15%; and (5) having a corrosion resistance of not greater than about 0.04 inch.

Claim 19

The refractory component of claim 14, wherein said refractory component is characterized as at least one article selected from the group consisting of a slide gate, a sub-entry nozzle and a ladle shroud.

Claim 20

The refractory component of claim 10, further comprising interconnected porosity which comprises a plurality of openings having a mean diameter of less than about 6 microns.

Claim 21

The refractory component of claim 1, wherein said refractory component comprises less than about 5 percent by weight zinc aluminate.

Claim 22

The refractory component of claim 1, wherein said filler material comprises at least one material selected from the group consisting of aluminum oxide and silicon carbide.

Claim 23

The refractory component of claim 1, wherein said filler material comprises at least one material selected from the group consisting of granules, particulates, powders, fibers, whiskers, aggregate, pellets, tubes, refractory fiber cloth, tubules and mixtures thereof.

Claim 24

The refractory component of claim 10, wherein said oxidant comprises an oxygen-containing gas and said oxidation reaction product comprises aluminum oxide.

Claim 25

The refractory component of claim 10, wherein said first temperature is from about 850° C. to about 1450° C.

Claim 26

The refractory component of claim 10, wherein said second temperature is greater than about 1250° C.

Claim 27

The refractory component of claim 10, wherein said filler material comprises at least one metal oxide, boride, nitride, or carbide of a metal selected from the group consisting of aluminum, cerium, hafnium, lanthanum, silicon, neodymium, praseodymium, samarium, scandium, thorium, uranium, titanium, yttrium, and zirconium.