Zirconium oxide fibers and process for their preparation

Claim 2

A silicon-free, green fiber comprising: (a) crystalline colloidal zirconia particles with diameters in the range of 5 to 200 nm, (b) at least one water soluble zirconium compound, and (c) residual solvent.

Claim 3

The green fiber according to claim 1 wherein said crystalline colloidal zirconia particles comprise 20 to 80 weight percent of the total zirconia equivalent present in said fiber.

Claim 4

The green fiber according to claim 1 wherein said soluble zirconia compound comprises 20 to 80 weight percent of the total zirconia equivalent present in said fiber.

Claim 5

The green fiber according to claim 1 wherein said soluble zirconium compound is zirconyl acetate.

Claim 6

The green fiber according to claim 1 wherein said solvent is water.

Claim 7

The green fiber according to claim 1 further comprising at least one of: (a) a water soluble compound or sol of metals whose oxides are phase change stabilizers for zirconium oxide wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (b) at least one water soluble compound or sol of metals whose oxides are grain growth inhibitors for zirconium oxide and wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (c) at least one water soluble catalyst or its precursor wherein said catalyst or precursor comprises more than 0 and up to 10 oxide equivalent mole percent of the total equivalent moles of zirconia present; and (d) a water soluble organic polymer wherein said polymer comprises more than 0 and up to 50 wt. percent of the total zirconia mass content of the fiber.

Claim 8

The green fiber according to claim 6 wherein said phase change stabilizer for zirconium oxide is a compound or sol of a metal selected from the group consisting of yttrium, magnesium, calcium, and cerium.

Claim 9

The green fiber according to claim 6 wherein said grain growth inhibitor is aluminum.

Claim 10

The green fiber according to claim 6 wherein said water soluble catalyst or its precursor is selected from the group consisting of chromium, cobalt, copper, iron, nickel, palladium, platinum and vanadium; their respective oxides, and their respective soluble salts or sols.

Claim 11

The green fiber according to claim 6 wherein said water soluble organic polymer is selected from the group consisting of polyethyleneglycol, polyethylene oxide, polyvinylacetate, polyvinylalcohol, and polyvinylpyrrolidone.

Claim 12

The green fiber according to claim 6 wherein said s organic polymer comprises 20 to 40 weight percent of the total zirconia content of said fiber.

Claim 13

A ceramic fiber comprising crystalline zirconia grains having a grain size of at most 1.0 micrometer, said fiber having a diameter in the range of 10 to 60 micrometers and a tensile strength greater than 0.5 GPa.

Claim 14

A ceramic fiber comprising crystalline zirconia grains having a grain size of at most 1.0 micrometer, said fiber having a diameter in the range of 10 to 60 micrometers and a tensile strength greater than 0.5 GPa.

Claim 15

A yarn prepared from the fibers of claim 12.

Claim 16

A knitted fabric prepared from the fibers of claim 13.

Claim 17

A woven or non-woven fabric prepared from the fibers of claim 12.

Claim 18

A process of making a ceramic fiber containing crystalline zirconia grains comprising the steps of: (a) mixing crystalline, colloidal zirconia particles, at least one soluble zirconium compound, and solvent; (b) concentrating said mixture; (c) extruding or blowing said fiber to provide a green fiber; and (d) heating said green fiber to a temperature in the range of 400° to 2000° C. in an oxygen-containing atmosphere to provide said fiber containing crystalline colloidal zirconia particles.

Claim 19

A process of making a ceramic fiber containing crystalline zirconia grains comprising the steps of: (a) mixing crystalline, colloidal zirconia particles, at least one soluble zirconium compound, and solvent; (b) concentrating said mixture; (c) extruding or blowing said fiber to provide a green fiber; and (d) heating said green fiber to a temperature in the range of 400° to 2000° C. in an oxygen-containing atmosphere to provide said fiber containing crystalline colloidal zirconia particles.

Claim 20

A process of making a ceramic fiber containing crystalline zirconia particles comprising the steps of: (a) mixing crystalline, colloidal zirconia particles, at least one soluble zirconium compound, solvent, and at least one of: (1) a water soluble compound or sol of metals whose oxides are phase change stabilizers for zirconium oxide wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (2) at least one water soluble compound or sol of metals whose oxides are grain growth inhibitors for zirconium oxide and wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (3) at least one water soluble catalyst or its precursor wherein said catalyst or precursor comprises more than 0 and up to 10 oxide equivalent mole percent of the total equivalent moles of zirconia present; and (4) a water soluble organic polymer wherein said polymer comprises more than 0 and up to 50 wt. percent of the total zirconia mass content of the fiber; (b) concentrating said mixture; (c) extruding or blowing said fiber to provide a green fiber; and (d) heating said green fiber to a temperature in the range of 400° to 2000° C. in an oxygen-containing atmosphere to provide said ceramic fiber containing crystalline colloidal zirconia particles.

Claim 21

A process of making a ceramic fiber containing crystalline zirconia particles comprising the steps of: (a) mixing crystalline, colloidal zirconia particles, at least one soluble zirconium compound, solvent, and at least one of: (1) a water soluble compound or sol of metals whose oxides are phase change stabilizers for zirconium oxide wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (2) at least one water soluble compound or sol of metals whose oxides are grain growth inhibitors for zirconium oxide and wherein said metals comprise more than 0 and up to 20 mole percent of the total equivalent moles of zirconia present; (3) at least one water soluble catalyst or its precursor wherein said catalyst or precursor comprises more than 0 and up to 10 oxide equivalent mole percent of the total equivalent moles of zirconia present; and (4) a water soluble organic polymer wherein said polymer comprises more than 0 and up to 50 wt. percent of the total zirconia mass content of the fiber; (b) concentrating said mixture; (c) extruding or blowing said fiber to provide a green fiber; and (d) heating said green fiber to a temperature in the range of 400° to 2000° C. in an oxygen-containing atmosphere to provide said ceramic fiber containing crystalline colloidal zirconia particles.

Claim 22

The ceramic fiber according to claim 16 which is a continuous fiber made by the process having a length greater than 1 meter.

Claim 23

A continuous, zirconia fiber prepared according to the process of claim 16, having a diameter in the range of 10 to 60 micrometers, and a tensile strength greater than 0.5 GPa.

Claim 24

The ceramic fiber according to claim 12 having a diameter in the range of 17 to 60 micrometers.