Phase Transformation of Pyrocarbon in Molten Sodium Metal

Abstract

A method to graphitize amorphous carbon was carried out by annealing pyrocarbon from cracked phenolic resin in molten sodium metal at a lower temperature and ambient pressure and the phase transformation of pyrocarbon from amorphous carbon to crystallized carbon was studied. X-ray diffraction (XRD), Raman scattering spectroscopy, transmission electron microscopy (TEM), and nitrogen gas physisorption by the Brunauer-Emmett-Teller (BET) method were used to probe the prepared samples for carbon composition, particle size, and morphology. The graphitization of amorphous carbon was obvious when being annealed in molten sodium metal in argon atmosphere at 800°C for 24 h. For the sample annealed at 900°C for 24 h, the degree of graphitization was 40% and the average thickness of the graphitized carbon layers was about 40 nm. The effect of sodium metal infiltration into the matrix of amorphous carbon on the graphitization is also discussed.