Method for making carbon nanotubes

Abstract

A method for making carbon nanotubes that includes the following steps. A metal substrate is provided. The surface of the metal substrate is polished. The polished metal substrate is put into a reaction device. A protecting gas is introduced to the reaction device while the environment inside of the reaction device is heated to about 400 to 800 degrees. A mixture of carbon source gas and protecting gas is introduced to the reaction device, whereby the carbon nanotubes are grown on the metal substrate on the polished metal substrate.

1 . A method for making carbon nanotubes, the method comprising the following steps:
 providing a metal substrate;   polishing a surface of the metal substrate;   putting the polished metal substrate into a reaction device;   introducing a first protecting gas while heating the environment inside of the reaction device to about 400 to 800 degrees; and   introducing a mixture of a carbon source gas and a second protecting gas, whereby the carbon nanotubes are grown directly on the polished metal substrate.   
     
     
         2 . The method as claimed in  claim 1 , wherein the step of polishing the surface of the metal substrate comprising the following steps:
 rubbing the surface of the metal substrate along a first direction; then   rubbing the surface of the metal substrate along a second direction; and then   repeatedly rubbing the surface of the metal substrate along the first direction.   
     
     
         3 . The method as claimed in  claim 2 , wherein the surface of the metal substrate is first rubbed along the first direction for about 3 to 5 minutes, then is rubbed along the second direction for about 5 to 8 minutes, and then is rubbed along the first direction for about 10 to 15 minutes. 
     
     
         4 . The method as claimed in  claim 2 , wherein the surface of the metal substrate is first rubbed along the first direction with an abrasive paper of about 600 to 800 grit, then is rubbed along the second direction with an abrasive paper of about 1000 to 1300 grit, and then is rubbed along the first direction with an abrasive paper of about 1500 to 2000 grit. 
     
     
         5 . The method as claimed in  claim 2 , wherein an angle between the first direction and the second direction is larger than 0 degrees and less than or equal to 90 degrees. 
     
     
         6 . The method as claimed in  claim 1 , further comprising a step of removing powder generated from polishing the surface of the metal substrate. 
     
     
         7 . The method as claimed in  claim 6 , wherein the powder is removed by the application of air flow. 
     
     
         8 . The method as claimed in  claim 1 , wherein the metal substrate comprises of copper. 
     
     
         9 . The method as claimed in  claim 1 , wherein the metal substrate is a rectangular. 
     
     
         10 . The method as claimed in  claim 1 , wherein a thickness of the metal substrate is in a range from about 0.5 centimeters to about 5 centimeters. 
     
     
         11 . The method as claimed in  claim 1 , wherein the reaction device is a box furnace or a tube furnace. 
     
     
         12 . The method as claimed in  claim 1 , wherein the first or second protecting gas is inert gas or nitrogen. 
     
     
         13 . The method as claimed in  claim 1 , wherein the carbon source gas is acetylene or ethylene. 
     
     
         14 . The method as claimed in  claim 1 , wherein a growth time for the carbon nanotubes is in a range from about 5 minutes to 30 minutes. 
     
     
         15 . The method as claimed in  claim 1 , wherein the first protecting gas and the second protecting gas comprise of the same gas.