Carbon nanotube compositions

Patent metadata

Field	Value
Publication number	US-2017190579-A1
Application number	US-201515325222-A
Country	US
Kind code	A1
Filing date	Jul 10, 2015
Priority date	Jul 10, 2014
Publication date	Jul 6, 2017
Grant date	—

Abstract

Metal-carbon nanotube composites having nanotubes which are uniformly dispersed within the metal matrix of the composite, and which are unbundled or substantially unbundled, have high lengths, and which can be controllably aligned are disclosed herein. Such metal-carbon nanotube composites can show improved electrical, thermal, and mechanical properties, as compared to a pristine metal or metal alloy which does not contain nanotubes dispersed therein. Facile and scalable methods of fabricating such metal-nanocarbon composites are also disclosed.

First claim

1 . A metal-carbon composite comprising:
a plurality of conformally coated carbon nanotubes having lengths in the range of 1-1000 microns which are uniformly dispersed within a metal or metal alloy matrix.

2 . The metal-carbon composite of claim 1 , wherein the conformal coating comprises a metal, metal oxide, carbonaceous, or polymeric material, which increases the wettability and dispersibility of the carbon nanotubes in the metal or metal alloy forming the matrix.

3 . The metal-carbon composite of claim 2 , wherein the conformal coating is a metal selected from aluminum, cobalt, chromium, zinc, tantalum, platinum, gold, nickel, iron, tin, lead, silver, titanium, indium, copper, combinations thereof, and metal oxides thereof.

4 . The metal-carbon composite of claim 2 , wherein the conformal coating is a carbonaceous material selected from pyrolytic carbon, graphite, single-layered graphene, and multi-layered graphene.

5 . The metal-carbon composite of claim 2 , wherein the conformal coating is a polymeric material selected from conjugated polymers or aromatic polymers.

6 . The metal-carbon composite of claim 2 , wherein the metal or metal alloy matrix comprises a metal selected from the group consisting of aluminum, copper, cobalt, chromium, zinc, tantalum, platinum, gold, nickel, iron, tin, lead, silver, titanium, indium, and combinations thereof.

7 . The metal-carbon composite of claim 1 , wherein the conformal coating material is associated to the surface of the nanotube through van der Waals bonds, π-π stacking, and/or covalent bonds

8 . The metal-carbon composite of claim 1 , further comprising a plurality of metallic particles on the surface of the conformally coated carbon nanotubes.

9 . The metal-carbon composite of claim 8 , wherein the metallic particles are selected from the group consisting of palladium nanoparticles, gold nanoparticles, silver nanoparticles, titanium nanoparticles, iron nanoparticles, nickel nanoparticles, copper nanoparticles, and combinations thereof.

10 . The metal-carbon composite of claim 1 , wherein the plurality of carbon nanotubes dispersed within the matrix have a controlled alignment along the in-plane direction, cross-plane direction, or along an intermediate-plane direction.

11 . The metal-carbon composite of claim 1 , wherein the composite has an electrical conductivity which is at least about 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, or higher than that of an electrical conductivity of a metal or metal alloy matrix which does not contain any dispersed carbon nanotubes.

12 . The metal-carbon composite of claim 1 , wherein the composite has a thermal conductivity which is at least about 20, 30, 50, or 70% greater than that of a thermal conductivity for metal or metal alloy matrix which does not contain any dispersed carbon nanotubes.

13 . The metal-carbon composite of claim 1 , wherein the composite has a coefficient of thermal expansion which is at least about 50, 40, 30, 20, or 10% of a coefficient of thermal expansion for an equivalent pristine metal or metal alloy.

14 . The metal-carbon composite of claim 1 , wherein the composite is in an interface between a heat sink and a chip and the composite has a thermal resistance of less than 1 mm 2 K/W.

15 . The metal-carbon composite of claim 1 , wherein the composite is in the form of a sheet, plate, foil, rod, wire, strip, ingot, pellet, or chunk.

16 . A method of making a metal-carbon composite, the method comprising the steps of:
1) preparing a carbon nanotube array on a substrate 2) conformally coating the carbon nanotubes on the substrate with one or more coating materials in an amount effective to increase the wettability, dispersibility, or both of the carbon nanotubes in a metal or metal matrix; 3) adding the conformally coated carbon nanotubes on the substrate to a melt of metal or metal alloy to form a mixture; and 4) cooling the mixture in order to form a metal-carbon nanotube composite wherein the carbon nanotubes are uniformly dispersed within the composite.

17 . The method of claim 16 , wherein the substrate is a foil comprising a metal or metal alloy.

18 . The method of claim 16 , wherein the carbon nanotube array is formed on one or both sides of the substrate or support.

19 . The method of claim 16 , wherein the melt of metal or metal alloy comprises a metal selected from the group consisting of aluminum, copper, cobalt, chromium, zinc, tantalum, platinum, gold, nickel, iron, tin, lead, silver, titanium, indium, and combinations thereof.

20 . The method of claim 16 , wherein the substrate is formed of metal which is different from the metal used to form the metal or metal alloy melt.

21 . The method of claim 16 , wherein the substrate melts at a higher temperature than the temperature of the melt of the metal or metal alloy melt in order to keep the substrate intact and the array of carbon nanotubes in their original orientation after the melt of the metal or metal alloy infiltrates the array.

22 . The method of claim 16 , further comprising the step of mechanical mixing or agitation of the mixture in order to control or improve the uniformity of the carbon nanotubes dispersed throughout the composite.

23 . The method of claim 16 , further comprising casting the mixture in a mold to form a sheet, plate, foil, rod, strip, ingot, pellet, or chunk after the step of cooling.

24 . The method of claim 23 , wherein the casting of the mixture in the mold further comprises applying pressure or weights to the mold.

25 . The method of claim 16 , wherein the conformal coating comprises a metal, metal oxide, carbonaceous, or polymeric material, which increases the wettability and dispersibility of the carbon nanotubes in the metal or metal alloy forming the matrix.

26 . The method of claim 25 , wherein the conformal coating is a metal selected from aluminum, cobalt, chromium, zinc, tantalum, platinum, gold, nickel, iron, tin, lead, silver, titanium, indium, copper, combinations thereof, and metal oxides thereof.

27 . The method of claim 25 , wherein the conformal coating is a carbonaceous material selected from pyrolytic carbon, graphite, single-layered graphene, and multi-layered graphene.

28 . The method of claim 25 , wherein the conformal coating is a polymeric material selected from conjugated polymers or aromatic polymers, which promote wetting of the carbon nanotubes to the melt of metal or metal alloy.

29 . A metal-carbon composite comprising:
a plurality of conformally coated carbon nanotubes, wherein at least one of the carbon nanotubes has a length in the range of 100-1000 microns, dispersed within a metal or metal alloy matrix.

30 . A metal-carbon composite comprising:
a plurality of conformally coated carbon nanotubes which are uniformly dispersed within a metal or metal alloy matrix.

Assignees

• Georgia Tech Res Inst

Inventors

• Cola Baratunde
• Spence Daron

Classifications

• C01B32/16

  Preparation · CPC title

• C01B2202/06

  Multi-walled nanotubes · CPC title

• Y10S977/847

  Surface modifications, e.g. functionalization, coating · CPC title

• Y10S977/784

  Electrically conducting, semi-conducting, or semi-insulating host material · CPC title

• C01B2202/22

  Electronic properties · CPC title