Abstract: The micro-crystallization structure and defect structure of domestic commodity carbon fiber and TORAY T300 carbon fiber were studied by XRD, HRTEM, and EDS. The results showed that the distance between graphite sheets (d₀₀₂), micro-crystallization piled thickness (Lc) and width (La) of domestic carbon fiber were same as T300 carbon fiber. And the orientation of crystalline of domestic fiber was higher than T300, but the depth of parallelism of domestic carbon fiber was smaller than T300. There was onion structure and some impurities elements in domestic carbon fiber, such as Ca, Si, and S.

Key words: PAN based carbon fiber, XRD, HRTEM, EDS, micro-crystallization structure, defect structure