Production of metal ion containing carbon fibers useful in electron shielding applications

An improved process for the production of a metal ion containing carbonaceous fibrous material wherein a metal nitride or a metal carbide is substantially uniformly dispersed in a carbon matrix capable of utilization in electron absorbing applications comprising:

• a. providing a spinning solution comprising (1) a fiber-forming acrylic polymer selected from the group consisting essentially of an acrylonitrile homopolymer and an acrylonitrile copolymer which contains at least about 85 mole percent of acrylonitrile units and up to about 15 mole percent of one or more monovinyl units copolymerized therewith, and (2) a spinning solvent selected from the group consisting essentially of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide,
• b. extruding said solution through a shaped orifice into a coagulation bath to form an as-spun fibrous material,
• c. contacting said as-spun fibrous material with an impregnation solution of a halide of a transition metal selected from the group consisting essentially of cobalt, hafnium, iron, molybdenum, nickel, niobium, tantalum, titanium, tungsten, uranium, vanadium, zirconium, and mixtures of the foregoing wherein said fibrous material is substantially uniformly impregnated with said halide from said impregnation solution, and with said halide of a transition element being provided in said solution in a concentration of about 2 to 60 percent by weight based upon the total weight of the solution,
• d. converting said halide of said transition metal present within said fibrous material to an oxide of said transition metal by contact with a solution of a base or a solution of an oxidizing agent,
• e. heating said acrylic fibrous material having said oxide of said transition metal incorporated therein in an oxygen-containing atmosphere at a temperature of about 220.degree. to 300.degree. C. until said fibrous material is thermally stabilized and rendered non-burning when subjected to an ordinary match flame, and
• f. heating said resulting stabilized fibrous material having an oxide of said transition metal incorporated therein in an atmosphere selected from the group consisting essentially of nitrogen, argon, and helium provided at a temperature of about 1,100.degree. to 3000.degree. C. for at least 15 seconds while retaining the original fibrous configuration substantially intact.

An improved process for the production of a metal ion containing carbonaceous fibrous material wherein a metal nitride or a metal carbide is substantially uniformly dispersed in a carbon matrix capable of utilization in electron absorbing applications comprising:

• a. providing a spinning solution comprising (1) about 12 to 20 percent by weight based upon the total weight of the solution of a fiber-formning acrylic polymer selected from the group consisting essentially of an acrylonitrile homopolymer and an acrylonitrile copolymer which contains at least about 85 mole percent of acrylonitrile units and up to about 15 mole percent of one or more monovinyl units copolymerized therewith, (2) about 1 to 40 percent by weight based upon the total weight of the solution of a halide of a transition metal selected from the group consisting essentially of cobalt, hafnium, iron, molybdenum, nickel, niobium, tantalum, titanium, tungsten, uranium, vanadium, zirconium, or mixtures of the foregoing dissolved therein, and (3) a spinning solvent selected from the group consisting essentially of N,N-dimethylformamide, N,N-dimethylacetamide and N,N-dimethylacetamide and dimethyl sulfoxide,
• b. extruding said solution through a shaped orifice into a coagulation bath wherein a fibrous material is formed and said halide is converted by contact with a solution of a base or a solution of an oxidizing agent to an oxide of a transition metal which is distributed throughout said fibrous material,
• c. heating said acrylic fibrous material having said oxide of said transition metal incorporated therein in an oxygen-containing atmosphere at a temperature of about 220.degree. to 300.degree. C. until said fibrous material is thermally stabilized and rendered non-burning when subjected to an ordinary match flame, and
• d. heating said resulting stabilized fibrous material having an oxide of said transition metal incorporated therein in an atmosphere selected from the group consisting essentially of nitrogen, argon, and helium provided at a temperature of about 1,100.degree. to 3,000.degree. C. for at least 15 seconds while retaining the original fibrous configuration substantially intact.