Morphological Changes on Micro-surface of Graphitized Carbon Fibers by Corrosion in a Hot Phosphoric Acid

摘要

A study was conducted by using SEM and AFM to evaluate the micro-structure of the corroded surface of two kinds of graphitized carbon fibers with different graphite crystal oreintation, i.e., the one of an onion-skin with random core structure and the other of simply a radical structure, respectively. It became clear that the former carbon fiber was corroded to increase its roughness on its surface slightly, while the latter was corroded to increase the surface roughness by more than three times (Ry) or six times (Ra) of the former. These results show that corrosion behavior of the carbon fiber changed by the orientation of graphite crystallite planes in both carbon fibers and the orientation of graphite crystallite planes is an imortant factor corrosion resistance along the graphitizability of the carbon fiber. Also, it was considered that these results are useful for other electrochemical applications, i.e., polymer electrolyte fuel cells with phosphoric acid fuel cells.