各向同性热解炭低温氧化行为研究

Low-temperature oxidation behavior of the isotropic pyrocarbons

利用自行设计的化学气相沉积(CVD)炉,以丙烯为碳源,氢气和氩气为载气,采用固定基体CVD法制备各向同性热解炭块体材料。通过恒温氧化实验对所获得的各向同性热解炭材料的低温(450℃)氧化行为进行研究,并与碳纳米管、炭黑和天然鳞片石墨进行比较。利用拉曼光谱(Raman)、扫描电镜(SEM)和透射电镜(TEM)等分析手段对氧化前后试样的表面形貌和微观结构进行表征。结果表明,炭材料的氧化特征与其内部的缺陷种类和密度密切相关,其中各向同性热解炭的抗氧化性能优于其他3种炭材料,其低温氧化过程服从直线规律,氧化反应主要发生于内部的条带状热解炭结构。

The bulk isotropic pyrocarbon materials were fabricated by fixed-bed chemical vapor deposition using graphite as substrate, propylene as carbon source, and hydrogen and argon as the carrier gas. The oxidation behavior at low temperature （450 ℃） of the isotropic pyrocarbon was studied using isothermal temperature oxidation method. In addition, comparative studies on natural graphite, carbon nanotube and carbon black were also carried out. The structures and surface morphologies of samples before and af- ter oxidation were characterized by Raman, SEM and TEM measurements. The results show that oxidation behavior of carbon materi- als is related with its internal defects. The oxidation resistance of the isotropic pyrocarbon is superior to those of the other three kinds of carbon materials. The curve of oxidation obeys linear regularity, and the oxidation reaction occurs mainly at the ribbon-like pyrolytic carbon.