Process for preparing ceramic compositions

Claim 2

The process of claim 1 in which the mixture is subjected to a pressure of at least about 100 pounds per square inch during the step of pressing said mixture while said ceramic-forming compound is decomposing.

Claim 3

The process of claim 1 in which during the step of heating the mixture to decompose said ceramic-forming compound the mixture is subjected to a temperature in the range of about 500* to 1,100*C, and during the step of pressing said mixture, the mixture is subjected to a pressure in the range of about 1,000 to 10,000 pounds per square inch.

Claim 4

The process of claim 1 in which said decomposable ceramic-forming compound is aluminum hydroxide.

Claim 5

The process of claim 1 in which said dopant is a fluorine-containing inorganic compound.

Claim 6

The process of claim 6 wherein said fluorine-containing compound is selected from the group consisting of LiF, MgF2, HF, AlF3 and CrF3.

Claim 7

The process of claim 1 wherein the dopant is a metal oxide selected from the group consisting of CoO, CrO3, Cr2O3, CuO, MO3, MnO, Nb2O5, NiO, TiO2, WO3, Y2O3, and ZrO2.

Claim 8

The process of claim 1 wherein said mixture is heated to a temperature of about 1,200*C while pressing to form a product having a density greater than 3.78.

Claim 9

A process for the preparation of a ceramic-metal composite including (1) a continuous ceramic matrix of alumina, of at least 50 percent by volume of the composite, and (2) a metal comprising less than 50 volume percent of the composite, comprising: a. implanting 50 parts by volume of a metal into more than 50 parts by volume of a mixture consisting essentially of, by weight, (i) about 60 to 99.99 percent of at least one ceramic-forming compound which decomposes at 300*C - 1,200*C to yield alumina, (ii) about 0.01 to 15 percent of at least one dopant selected from the group consisting of fluorine-containing inorganic compounds and metal oxides and (iii) about 0 to 39.99 percent of non-metallic material that is non-decomposable at 300*C - 1,200*C; b. heating said mixture to about 300*C - 1,200*C to decompose said ceramic-forming compound, said metal having a melting point above the temperature in the range of 300*C - 1,200*C to which said mixture is heated in step (b) to decompose said ceramic-forming compound; c. pressing said mixture during said heating to shape, strengthen and densify said mixture to produce a ceramic-metallic composite having a continuous ceramic matrix and a density greater than 3.42 after cooling.

Claim 10

The process of claim 10 in which by weight, about 80 to 99.5 percent of decomposable ceramic-forming compound, about 0.5 to 5 percent of dopant, and about 0 to 15 percent of non-decomposable material are mixed in step (a).

Claim 11

The process of claim 10 in which said mixture containing the metal is heated to about 500*C to 1,100*C, and simultaneously pressed at about 1,000 to 10,000 pounds per square inch.

Claim 12

The process of claim 10 wherein said decomposable ceramic-forming compound is aluminum hydroxide.

Claim 13

The process of claim 10 wherein said metal is selected from the group consisting of copper, iron, nickel, titanium, steel, and nickel and chrome alloys.

Claim 14

The process of claim 10 wherein the metal is an interconnected structure.

Claim 15

The process of claim 10 wherein the mixture is heated to a temperature of about 1,200*C to form a product having a continuous ceramic matrix and a density greater than 3.78.

Claim 16

The process of claim 1 wherein said dopant is a fluorine-containing inorganic compound selected from the group consisting of LiF, MgF2, HF, AlF3 and CrF3.

Claim 17

The process of claim 1 wherein the dopant is a metal oxide selected from the group consisting of CoO, CrO3, Cr2O3, CuO, MO3, MnO, Nb2O5, NiO, TiO2, WO3, Y2O3 and ZrO2.

Claim 18

A process for the preparation of a magnesia ceramic product having a continuous ceramic matrix, and a density greater than 3.40, 3,40, comprising: a. mixing, by weight, (i) about 80 to 99.99 percent of Mg(OH)2; (ii) about 0.5 to 5 percent of at least one dopant selected from the group consisting of fluorine-containing inorganic compounds and metal oxides; and (iii) about 0 to 15 percent of a non-metallic, non-decomposable filler material which is nondecomposable at temperatures of about 860*C; b. heating said mixture to 860*C to decompose said Mg(OH)2; and c. pressing said mixture at 3,000 psi during decomposition of the MgOH2 to shape, strengthen and densify said mixture, and produce a product having a continuous ceramic matrix and a density greater than 3.40 after cooling.

Claim 19

A process for the preparation of a magnesia ceramic product having a continuous ceramic matrix, and a density greater than 3.40, comprising: a. mixing, by weight (i) 80 to 99.99 percent of Mg(OH)2; (ii) about 0.5 to 5 percent of at least one dopant selected from the group consisting of fluorine-containing inorganic compounds and metal oxides; and (iii) about 0 to 15 percenT of a non-metallic, non-decomposable filler material which is non-decomposable at temperatures of 1,100*C; b. heating said mixture to 1,100*C to decompose said Mg(OH)2; and c. pressing said mixture at 4,000 psi during decomposition of the MgOH2 to shape, strengthen and densify said mixture, and produce a product having a continuous ceramic matrix, and a density greater than 3.40 after cooling.

Claim 20

A process for the preparation of a magnesia ceramic product having a continuous ceramic matrix, and a density greater than 3.40, comprising: a. mixing, by weight, 80 to 99.99 percent of Mg(OH)2; about 0.5 to 5 percent of at least one dopant selected from the group consisting of fluorine-containing inorganic compounds and metal oxides and about 0 to 15 percent of a non-metallic, non-decomposable filler material which is non-decomposable at temperatures of 960*C; b. heating said mixture to 960*C to decompose said Mg(OH)2; and c. pressing said mixture at 3,000 psi during decomposition of the MgOH2 to shape, strengthen and densify said mixture, and produce a product having a continuous ceramic matrix, and a density greater than 3.40 after cooling.

Claim 21

A process for the preparation of a magnesia ceramic product having a continuous ceramic matrix, and a density greater than 3.40, comprising: a. mixing, by weight, 80 to 99.99 percent of Mg(OH)2; about 0.5 to 5 percent of at least one dopant selected from the group consisting of fluorine-containing inorganic compounds and metal oxides; and about 0 to 15 percent of a non-metallic non-decomposable filler material which is non-decomposable at temperatures of 910*C; b. heating said mixture to 910*C to decompose said Mg(OH)2; and c. pressing said mixture at 3,000 psi during decomposition of the MgOH2 to shape, strengthen and densify said mixture, and produce a product having a continuous ceramic matrix and a density greater than 3.40 after cooling.

Claim 22

The process of claim 19, including the step of implanting 50 parts by volume of a metal into more than 50 parts by volume of said mixture, prior to the steps of heating and pressing said mixture.

Claim 23

The process of claim 20, including the step of implanting 50 parts by volume of a metal into more than 50 parts by volume of said mixture, prior to the steps of heating and pressing said mixture.

Claim 24

The process of claim 21, including the step of implanting 50 parts by volume of a metal into more than 50 parts by volume of said mixture, prior to the steps of heating and pressing said mixture.

Claim 25

The process of claim 22, including the step of implanting 50 parts by volume of a metal into more than 50 parts by volume of said mixture, prior to the steps of heating and pressing said mixture.