Fullene based sintered carbon materials

• US 6,783,745 B1
• Filed: 03/12/2001
• Issued: 08/31/2004
• Est. Priority Date: 09/14/1998
• Status: Expired due to Fees

• Current Assignee: Diamond Materials Inc.
• Original Assignee: Diamond Materials Inc.
• Inventors: Voronov, Oleg A., Tompa, Gary S.
• Primary Examiner(s): Hendrickson, Stuart L.
• Assistant Examiner(s): Lish, Peter J
• Application Number:
  US09/787,015
• Time in Patent Office: 1,268 Days
• Field of Search: 423/445.B, 423/446, 423/447.2, 428/408, 427/249.12
• US Class Current: 423/446
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C04B 2235/3817 Carbides
• CPC Class Codes: C04B 2235/3821 Boron carbides
• CPC Class Codes: C04B 2235/3843 Titanium carbides
• CPC Class Codes: C04B 2235/422 Carbon
• CPC Class Codes: C04B 2235/425 Graphite
• CPC Class Codes: C04B 2235/427 Diamond
• CPC Class Codes: C04B 2235/486 Boron containing organic compounds, e.g. borazine, borane or boranyl
• CPC Class Codes: C04B 2235/5288 Carbon nanotubes
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/94 Products characterised by their shape
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/52 based on carbon, e.g. graphite
• CPC Class Codes: C04B 35/528 obtained from carbonaceous particles with or without other non-organic components
• CPC Class Codes: C04B 35/62695 Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C04B 35/63 using additives specially adapted for forming the products , e.g.. binder binders
• CPC Class Codes: C04B 35/645 Pressure sintering
• CPC Class Codes: C22C 2026/001 : Fullerenes
• CPC Class Codes: C22C 2026/002 : Carbon nanotubes
• CPC Class Codes: C22C 26/00 : Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
• CPC Class Codes: Y10S 977/749 : Modified with dissimilar atoms or molecules substituted for carbon atoms of the cnt, e.g. impurity doping or compositional substitution
• CPC Class Codes: Y10S 977/896 : Chemical synthesis, e.g. chemical bonding or breaking
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A new class of carbon materials and their synthesis. The new carbon materials are formed by high pressure and high temperature processing of fullerene based carbon powder. The new carbon materials are harder than graphite and can be harder than steel (what the starting fullerenes are single wall nanotubes) or almost as hard as diamond (when the starting fullerened arm C₆₀ buckyballs). The physical attributes of the materials can also be controlled by the pressing and heating parameters. These new carbon materials are conductive like graphite and unlike diamond which is an insulator. The materials can be formed by powder metallurgy techniques into any shape (cylinders, balls, tubes, rods, cones, foils, fibers or others). The new materials can also be readily doped, converted to diamond, formed within a porous composite or converted to diamond within the porous composite.

Claims

1. A hard carbon material having a density greater than 2.3 g/cm³ and a hardness from 1.0 Gpa to 50 Gpa formed by the process of:

a) providing a fullerene based carbon powder comprising at least 99% single walled nanotubes,

b) agglomerating said fullerene based carbon powder to a density above 1.4 g/cm³;

c) subjecting said fullerene based carbon powder to a pressure of 1.0 to 10.0 Gpa, a temperature of from 300-1000°

C. for a period of time from 1 to 10000 seconds.

2. The carbon material as claimed in claim 1, wherein the fullerene based powder comprises at least 99.9% single walled nanotubes.

3. The carbon material as claimed in claim 1, wherein the pressure is at least 2.5 GPa, the temperature is at least 500°

C., and the period of time is at least 1000 seconds.

4. The carbon material as claimed in claim 1, wherein the fullerene based powder comprises 0.0001 to 1.0% of a dopant to effect the electrical properties of the material.

5. The carbon material as claimed in claim 4, wherein the dopant is selected from the group consisting of hydrogen, boron, nitrogen, oxygen, sulphur, fluorine, and chlorine.

6. A process for forming a high density sintered conductive carbon material, having a hardness from 1.0 Gpa to 50 Gpa, comprising the steps of:

a) providing an fullerene based carbon powder having at least 99.9% by weight of single walled nanotubes,

b) agglomerating said fullerene based carbon powder to a density above 1.4 g/cm³;

c) subjecting said fullerene based carbon powder to pressure of 1.0 to 10.0 Gpa, a temperature of from 300-1000°

C. for a period of time of from 1 to 10000 seconds.

7. The process as claimed in claim 6, further including the steps of infiltrating said fullerenes by superplastic flow under temperature and pressure into a porous composite material and said subjecting step takes place after said fullerene based carbon powder has been infiltrated into the porous material.

8. The process as claimed in claim 7, wherein the superplastic flow takes place at temperatures of 200-400°

C. at pressures of 0.1-1.0 Gpa.

9. The process as claimed in claim 6, wherein the fullerene based carbon powder comprises 0.0001 to 1.0% of a dopant to effect the electrical properties of the material.

10. A conductive hard, high density carbon material comprising at least 99.9% by weight of single walled nanotubes subjected to heat, temperature and pressure sufficient to provide a hardness to the material of at least 1.0 Gpa and less than 50 Gpa with a resistivity of less than 10 ohms-cm and a density above 2.3 g/cm³.

11. The material as claimed in claim 10, further including 0.0001 to 1.0% of a dopant to effect the electrical properties of the material.

12. A process for forming a high density sintered conductive carbon material, having a hardness from 1.0 Gpa to 50 Gpa, comprising the steps of:

a) providing an fullerene based carbon powder having at least 99.9% buckyballs

b) agglomerating said fullerene based carbon powder to a density above 1.4 g/cm³;

c) subjecting said fullerene based carbon powder to pressure of 1.0 to 10.0 Gpa, a temperature of from 300-1000°

C. for a period of time of from 1 to 10000 seconds;

d) providing an alloy used to convert carbon materials to diamond, and

e) subjecting said carbon material to a pressure of 7.0 to 9.0 Gpa, a temperature of from 800-1300°

C. for a period of time from 0.1 to 100 seconds to convert the carbon material to polycrystalline diamond.

13. The process as claimed in claim 12, wherein the alloys are based on at least one of Ni, Fe and Co.

14. A process for forming a high density sintered conductive carbon material, having a hardness from 1.0 Gpa to 50 Gpa, comprising the steps of:

a) providing an fullerene based carbon powder having at least 99.9% buckyballs

b) agglomerating said fullerene based carbon powder to a density above 1.4 g/cm³;

c) subjecting said fullerene based carbon powder to pressure of 1.0 to 10.0 Gpa, a temperature of from 300-1000°

C. for a period of time of from 1 to 10000 seconds;

d) providing a metal alloy selected form the group comprising aluminum, magnesium and calcium alloys; and

e) subjecting said carbon material to a pressure of 2.5 to 9.0 Gpa, a temperature of from 400-1300°

C. for a period of time from 10 to 1000 seconds to convert the carbon material to monocrystalline diamond.

15. A process for forming a high density sintered conductive carbon material, having a hardness from 1.0 Gpa to 50 Gpa, comprising the steps of:

a) providing an fullerene based carbon powder having at least 99% fullerenes,

b) agglomerating said fullerene based carbon powder to a density above 1.4 g/cm³;

c) infiltrating said fullerenes by superplastic flow under temperature and pressure into a porous composite material; and

c) subjecting said infiltrated composite material to pressure of 1.0 to 10.0 Gpa, a temperature of from 300-1000°

C. for a period of time of from 1 to 10000 seconds.