类玻璃炭孔隙结构的TEM考察

主要探讨酚醛树脂为前驱物的类玻璃炭,在炭化及石墨化至2 400 ℃过程中,利用透射电子显微镜观察其微结构的变化.发现一些明显的微晶碳层平面完好地堆栈在孔洞周围,这些碳层结晶尺寸在20 nm～200 nm之间.同时,这些碳层平面排列十分整齐并延伸至孔洞的表面,这些排列完好的碳层平面主要是因在小分子物气化过程中所产生.这个气化反应会生成像石墨化应力的效果,导致在孔洞内部及边缘形成高结晶碳层平面.

The pore structure of a glass-like carbon as revealed by transmission electron microscopy

Phenolic resin was heat-treated up to 2 400 ℃ in an argon flow, leading to the formation of porous graphitized products. The microstructural changes in the graphitized phenolic resin were investigated by transmission electron microscopy. Some oval-shaped crystallites from 20 to 200 nm and with very regular order have been found, which extend to the surface of the pores. In general, the larger the pores, the larger are the crystallites inside them, and there are smaller crystallites between the larger crystallites. The formation of the crystallites is due to the gas evolution reaction, evaporation of which creates an effect analogous to stress graphitization, leading to these highly directional crystallites at the edges and inside the pores.