I am currently doing thermal treatment for CNTs and graphene in the vacuum environment. I understand that the carbon atoms on the surface of CNTs and graphene reorganize at high temperature. Depending on the temperature, crystallinity can be improved or heavily changed into other graphitic structures, e.g. coalescence of CNT walls. If the temperature is too high, crystal structure will be transformed into amorphous phase or even evaporated.
Could anyone please tell me the temperature threshold for the amorphous transformation and for the evaporation process? I guess they are relating to the thermal response of graphite. And if possible, is there any good paper or book that can help me to understand more about this process of CNTs, graphene, or graphite in inert environment?
Thanks.
In my opinion, the upper answers are wrong, concerning the melting temperature of CNTs or graphene. The critical temperature you want is the intrinsic stability temperature of the structure, and I think it approaches 3000K or even more, depending on the quality of vacuum. Look at this paper for more information:Melting of graphene: from two to one dimension
i have used CNTsonly for for reinforcing materials in my Nanocomposite development. I am not in a position to answer your question hoewver I think you should check the University of Manchester research work on Graphene and may be for CNTs.
for the carbon componds evaporation temperature is 300-500c (as i know) in normal atmosphere , insted of going for vacuum why dont you try using inert atmosphere or inert mixture atmoshpher
I dont know exactly weather, after thermal treatment to the CNT they can be transformed into amorphous carbon or not but for the removal of carbon you need to anneal it above 500 oC or 500 oC
In my opinion, the upper answers are wrong, concerning the melting temperature of CNTs or graphene. The critical temperature you want is the intrinsic stability temperature of the structure, and I think it approaches 3000K or even more, depending on the quality of vacuum. Look at this paper for more information:Melting of graphene: from two to one dimension
The melting temperature of graphene was calculated to be 4510K. Please see this publication: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.045415
regarding CNTs, SWCNTS are melting at 4800K as the theory predicts: http://iopscience.iop.org/0957-4484/18/28/285703
In inert atmosphere (nitrogen or Ar), we CVD-grow SWNT at 900C so they can survive at least that high. To remove amorphous carbon, we heat up to 250-300C in air
CNT's have different temperatures which depends on the technique you have used to synthesize. also depends on the purity... metal content and so on. So, you must run before you start your experiments a TGA of your CNT's iin order to know the oxidation temperature. Also, as some colleagues mentioned above, the atmosphere its important and you select it depending on what you want to obtain. All the best.
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