Hollow ceramic fibers

Claim 2

A hollow metal oxide, carbide, nitride or boride fiber, or a hollow metal fiber, having a fiber outer diameter of less than about 50 microns.

Claim 3

A fiber according to Claim 1 or a method of Claim 3 or 4 wherein the metal is titanium, tin, zirconium, yttrium, nickel or calcium.

Claim 4

A method for producing the hollow metal oxide, carbide, nitride or boride fiber of Claim 1 comprising: . a) immersing a carbon fiber capable of absorbing at least twice its weight in liquid in a solution of a metal salt capable of being calcined to its oxide or converted to its carbide, nitride or boride, for from about 10 minutes to about 36 hours and at a pH ranging from about 3 to about 10, to thereby impregnate the carbon fiber with salt, b) drying the resultant, impregnated carbon fiber. c) calcining or converting the dried, impregnated fiber to transform the salt to its corresponding oxide, carbide, nitride or boride and remove the carbon fiber, and d) recovering the resultant hollow fiber.

Claim 5

A method of producing the hollow metal fiber of Claim 1 comprising: a) immersing a carbon fiber capable of absorbing at least twice its weight in liquid in a solution of a metal salt capable of being calcined to its oxide or converted to its carbide, nitride or boride, for from about 10 minutes to about 36 hours and at a pH ranging from about 3 to about 10, to thereby impregnate the carbin fiber with salt, b) drying the resultant, impregnated carbon fiber, c) calcining or converting the dried, impregnated fiber to transform the salt to its corresponding oxide, carbide, nitride or boride and remove the carbon fiber, d) reducing the so-formed, calcined or converted fiber and e) recovering the resultant hollow metal fiber.

Claim 6

A method of Claim 3 or 4 wherein the carbon fiber is activated carbon fiber.

Claim 7

A method of Claim 3 or 4 wherein the carbon fiber is oxidized carbon fiber.

Claim 8

A hollow metal oxide, carbide, nitride or boride fiber of Claim 1, or a method of Claim 3, wherein the metal is a mixture of zirconium and at least one of yttrium, calcium and magnesium, or wherein the metal is barium titanate.

Claim 9

A hollow metal oxide, carbide, nitride or boride fiber of Claim 1 or a method of Claim 3 wherein the metal is a mixture of metals.

Claim 10

A fiber or method of Claim 8 with the mixture comprising metals selected from the group consisting of: beryllium, magnesium, calcium, barium, strontium, yttrium, lanthanium, cerium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, cadmium, boron, aluminum, gallium, gadolinium, silicon, tin, lead, thorium, uranium, plutonium, palladium, platinum, rhodium, and iridium.

Claim 11

A fiber or method of Claim 9 with the mixture comprising (a) lead, zirconium, and titanium; (b) lead, zirconium, titanium, and niobium; or (c) gallium and gadolinium.

Claim 12

A hollow metal fiber of Claim 1 or a method of Claim 4 wherein the metal is a mixture of metals.

Claim 13

A fiber or method of Claim 11 with the mixture comprising metals selected from the group consisting of: beryllium, calcium, barium, strontium, yttrium, lanthanium, cerium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, cadmium, aluminum, gallium, gadolinium, silicon, tin, lead, thorium, uranium, plutonium, palladium, platinum, rhodium, and iridium.