Surface oxidation and/or corrosion behavior of vapor-grown carbon fibers (VGCFs) in nitric acid, hydrogen peroxide, and sulfuric acid solutions

摘要

The surface oxidation and/or corrosion behavior of vapor-grown carbon fibers (VGCFs) in acidic and oxidizing solutions was investigated with X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. In HNO3, the O/C atom ratio varied with the relative amounts of different oxygen-containing species, and an etched skin was observed. In aqueous H2O2, a rough surface was observed without change in the O/C atom ratio. In concentrated H2SO4, the relative amounts of sulfur-containing species drastically changed, and a pressed-like skin was observed. In diluted H2SO4, the relative amounts of sulfur- and oxygen-containing species changed; etched and pressed-like skins were both observed. Sulfite group was more stable than sulfate one on the H2SO4-solution treated surfaces.