一种热解炭在金属钠中的相变.pdf

物理化学学报( Lli Huaxue Xuebao)
262
Acta Phys -Chim. Sin, 2011, 27(1): 262-266
nuat
Article
www.whxb.pku.edu.cn
种热解炭在金属钠中的相变
徐子颉”吉涛王玮衍夏炳忠马超甘礼华
(同济大学化学系,上海200092)
摘要:通过酚醛树脂的裂解和碳化所形成的热解炭与金属钠在气保护气氛中加热,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射线粉末行射
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24h,发生明显的石墨化;于900C加热24h,所得样品
的石墨化度为40%,石墨化碳的平均厚度约为40nm,孔结构由微孔转变为介孔.探讨了金属钠在无定形碳中
的滲透扩散导致其相变的原因
关键词:酚醛树脂;热解炭;石黑化;属钠;相变
中图分类号:O642;O792
Phase Transformation of Pyrocarbon in Molten Sodium Metal
XU ZI-JIE"JI Tao WANG Wei-yan XIA Bing-zhong MA Chao GAN Li-hua
(Department of Chemistry, Tongii University hanghai 200092, RR. China
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 amor hous 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 composion, pati size and mophology. 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
900C 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
Key Words: Phenol resin; Pyrocarbon; Graphitization; Sodium metal Phase transformation
炭/炭复合材料是一种多相非均质混合物,因其的应用具有重要的意义
具有高比强度、高比模量等显著的材料结构性能,逐
无定形碳的石瞾化就是在一定的二维平面范
渐成为新一代航空航天材料的发展方向.然而炭/炭围内有序的乱层结构碳的残片进行定向重排的相
复合材料的石墨化,会影响该类材料的力学性能、物变过程.由于在该相变过程中,无定形碳容易形成
理性能和化学性能,是最重要的结构控制因素之
亚稳态,使得这种相变的阻力增大,因此商品化石
通过调整该类材料的石墨化状态,可改善其综合性墨的生产一般都在27009C左右进行.但是,在如此
能,从而满足不同的使用要求.因此,开展无定形碳高温条件下进行石墨化,使得材料的力学和电学性
材料在较低温度下的石斝化研究村炭/炭复合材料能受到损害,如无定形碳材料在2700C经石墨化
Received: August 9, 2010; Revised: September 12, 2010; Published on Web: November 15, 2010
CorrespondingauthorEmail:xuzijie-ti(@126.com;Tel:+86-21-65982654-8430
C Editorial office of Acta Physico-chimica Sinica