Surface morphology and in-situ observation on the oxidation behavior of carbon materials by laser microscopy

Abstract

Surface morphology and in-situ observation on the oxidation behavior of same carbon materials were investigated by laser microscope. From the observation of surface morphology of carbon fiber, glass-like carbon, C/C composite, natural graphite and heat-treated polyimide films, samples with relatively flat surface and with homogeneous reflectivity, such as glass-like carbon, natural graphite and heat-treated polyimide films, were found to be observed clearly and accurately with the limit of detectable scale of 0.1μm. From in-situ observation on oxidation behavior in air, oxidation of glass-like carbon was observed to start from surface flaw streaks, from boundary region of filler in matrix and from small pits in the matrix. And oxidation proceeded almost same speed along three dimensional all directions in the sample. On the other hand, oxidation of natural graphite and heat-treated polyimide film started from edge of graphite layer and proceeded two dimensionally along graphite layer plane. Particularly it was found that structure and texture of heat-treated polyimide films affected it's oxidation behavior. It was suggested that structure and texture of carbon materials could be clarified from in-situ observation of oxidation behavior by laser microscope.