Method of making self-supporting ceramic materials and materials made thereby

Claim 1

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant and (ii) at least one non-oxidized constituent of the parent metal.

Claim 2

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant and (ii) at least one non-oxidized constituent of the parent metal.

Claim 4

The method of claims 1 or 2 wherein the parent metal comprises aluminum initially alloyed with (a) magnesium and zinc, or (b) magnesium and silicon, or (c) magnesium, zinc and silicon and is heated in air at a temperature of from about 850° C. to about 1450° C. for a time sufficient to produce said ceramic body consisting essentially of alpha-alumina and at least one structural feature selected from the group consisting of non-oxidized constituents of the parent metal and voids, said at least one structural feature being at least partially interconnected.

Claim 5

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature from about 850° C. to about 1450° C. to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant and at least one non-oxidized constituent of the parent metal thereby producing said ceramic body.

Claim 6

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature from about 850° C. to about 1450° C. to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant and at least one non-oxidized constituent of the parent metal thereby producing said ceramic body.

Claim 10

The method of claims 4, 5 or 6 wherein the dopant material comprises a source of silicon plus a source of one or both of magnesium and zinc.

Claim 11

The method of claims 4, 5 or 6 wherein the dopant material is selected from the group consisting of a source of one or both of magnesium and zinc plus a source of one or more of silicon, germanium, tin, lead, boron, sodium, lithium, and rare earth metal.

Claim 13

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of the oxidation reaction product of said parent metal with said vapor-phase oxidant.

Claim 14

A method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of the oxidation reaction product of said parent metal with said vapor-phase oxidant.

Claim 16

The method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant, (ii) at least one non-oxidized constituent of the parent metal, and (iii) at least one dopant constituent.

Claim 17

The method for producing a self-supporting ceramic body, said body being produced from an oxidation reaction between a molten parent metal and a vapor-phase oxidant and said body being adapted or fabricated for use as an article of commerce, the method comprising: (a) applying a layer of dopant material to at least a portion of a surface of a parent metal to provide thereon a dopant-carrying surface; (b) heating said parent metal to a temperature above its melting point but below the melting point of its oxidation reaction product to form a body of molten parent metal, and at said temperature (i) reacting the molten parent metal by initially contacting said dopant-carrying surface thereof with said vapor-phase oxidant to form an oxidation reaction product and (ii) 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 therethrough towards the oxidant such that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product; and (c) continuing said reaction for a time sufficient to grow said oxidation reaction product through and beyond the applied layer of dopant material, thereby resulting in said ceramic body which consists essentially of (i) the oxidation reaction product of said parent metal with said vapor-phase oxidant, (ii) at least one non-oxidized constituent of the parent metal, and (iii) at least one dopant constituent.

Claim 19

The method of any of claims 1, 2, 11, 12, 13 or 14 wherein said layer of dopant material comprises a source of two or more dopants.

Claim 30

The method of any of claims 1, 2, 11, 12, 13 or 14 wherein said dopant material comprises a source of one or more of magnesium, zinc, silicon, germanium, tin, lead, boron, sodium, lithium, calcium, phosphorus, yttrium, and rare earth metal.

Claim 35

The method of any of claims 1, 2, 11, 12, 13 or 14 wherein said oxidant is selected from the group consisting of an oxygen-containing gas, a nitrogen-containing gas, a halogen, sulfur, phosphorus, arsenic, carbon, boron, selenium, tellurium, methane, ethane, propane, acetylene, ethylene, propylene, and mixtures thereof.

Claim 40

The method of any of claims 2, 12 or 14 including maintaining said temperature from about 850° C. to about 1450° C.

Claim 42

The method of any of claims 1, 2, 11, 12, 13 or 14 wherein at least one of a first dopant material is applied to said parent metal in said layer and at least one of a second dopant material is alloyed in said parent metal.

Claim 43

The method of any of claims 1, 2, 11, 12, 13 or 14 wherein the layer of dopant material comprises a sheet of dopant-containing material overlaid on said surface of said parent metal.

Claim 45

The method of claims 1, 2, 4, or 5 wherein said ceramic body further includes an initiation surface of a spinel formed as an oxidation reaction product of said parent metal, said dopant and said oxidant.