Metal material and method of producing the same, and carbon fiber-metal composite material and method of producing the same
View Patent ↗A method of producing a metal material in which carbon nanofibers are dispersed around metal particles includes: (a) mixing an elastomer which includes an unsaturated bond or a group having affinity to the carbon nanofibers, the metal particles, and the carbon nanofibers, and dispersing the carbon nanofibers by applying a shear force to obtain a carbon fiber composite material; and (b) heat-treating the carbon fiber composite material to vaporize the elastomer in the carbon fiber composite material.
1. A method of producing a metal material in which carbon nanofibers are uniformly dispersed around metal particles, the method comprising:
(a) mixing an elastomer which includes an unsaturated bond or a group having affinity to the carbon nanofibers, the metal particles, and the carbon nanofibers, and dispersing the carbon nanofibers by applying a shear force to obtain a carbon fiber composite material; and
(b) heat-treating the carbon fiber composite material to vaporize the elastomer in the carbon fiber composite material at a temperature that is equal to or higher than a vaporization temperature of the elastomer and less than a melting point of the metal particles to obtain the metal material.
2. The method of producing a metal material as defined in claim 1 ,
wherein the metal particles are mixed in an amount of 10 to 3,000 parts by weight for 100 parts by weight of the elastomer.
3. The method of producing a metal material as defined in claim 1 , wherein the metal particles have an average particle diameter greater than an average diameter of the carbon nanofibers.
4. The method of producing a metal material as defined in claim 1 , wherein the metal particles have an average particle diameter of 500 μm or less.
5. The method of producing a metal material as defined in claim 1 , wherein the metal particles are aluminum particles or aluminum alloy particles.
6. The method of producing a metal material as defined in claim 1 , wherein the elastomer has a molecular weight of 5,000 to 5,000,000.
7. The method of producing a metal material as defined in claim 1 ,
wherein at least one of a main chain, a side chain, and a terminal chain of the elastomer includes at least one of a double bond, a triple bond, α-hydrogen, a carbonyl group, a carboxyl group, a hydroxyl group, an amino group, a nitrite group, a ketone group, an amide group, an epoxy group, an ester group, a vinyl group, a halogen group, a urethane group, a biuret group, an allophanate group, and a urea group.
8. The method of producing a metal material as defined in claim 1 , wherein a network component of the elastomer in an uncrosslinked form has a spin-spin relaxation time (T 2 n ) measured at 30° C. by a Hahn-echo method using a pulsed nuclear magnetic resonance (NMR) technique of 100 to 3000 μsec.
9. The method of producing a metal material as defined in claim 1 , wherein a network component of the elastomer in a crosslinked form has a spin-spin relaxation time (T 2 n ) measured at 30° C. by a Hahn-echo method using a pulsed nuclear magnetic resonance (NMR) technique of 100 to 2000 μsec.
10. The method of producing a metal material as defined in claim 1 ,
wherein the carbon nanofibers have an average diameter of 0.5 to 500 nm.
11. The method of producing a metal material as defined in claim 1 ,
wherein the step (a) is performed by using an open roll method with a roll interval of 0.5 mm or less.
12. The method of producing a metal material as defined in claim 11 ,
wherein two rolls used in the open-roll method have a surface velocity ratio of 1.05 to 3.00.
13. The method of producing a metal material as defined in claim 1 , wherein the step (a) is performed at 0 to 50° C.
14. The method of producing a metal material as defined in claim 1 ,
wherein the step (b) is performed in an inert gas atmosphere at a temperature equal to or higher than a vaporization temperature of the elastomer and less than a melting point of the metal particles.
15. The method of producing a metal material as defined in claim 1 ,
wherein the elastomer is natural rubber (NR);
wherein the metal particles are aluminum particles; and
wherein a heat treatment temperature in the step (b) is 300 to 650° C.
16. A method of producing a carbon fiber-metal composite material, the method comprising:
powder forming the metal material obtained in claim 1 .
17. A method of producing a carbon fiber-metal composite material, the method comprising:
mixing the metal material obtained in claim 1 into a molten metal and casting a mixture of the metal material and the molten metal in a die having a desired shape.
18. A method of producing a carbon fiber-metal composite material, the method comprising:
causing a molten metal to permeate the metal material obtained in claim 1 to fill a space in the metal material with the molten metal.