一种热解炭在金属钠中的相变

通过酚醛树脂的裂解和碳化所形成的热解炭与金属钠在氩气保护气氛中加热, 得到一种无定形碳在常压和较低温度下进行石墨化的方法, 并研究了热解炭在金属钠熔体中的相变. 对所得样品用X射线粉末衍射(XRD)、光散射拉曼光谱、透射电子显微镜(TEM)以及Brunauer-Emmett-Teller (BET)法氮气吸附进行表征与分析. 结果表明: 热解炭在金属钠熔体中于800 °C加热24 h, 发生明显的石墨化; 于900 °C加热24 h, 所得样品的石墨化度为40%, 石墨化碳的平均厚度约为40 nm, 孔结构由微孔转变为介孔. 探讨了金属钠在无定形碳中的渗透扩散导致其相变的原因.

Phase Transformation of Pyrocarbon in Molten Sodium Metal

Amethod 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.