Cone-Shaped Graphitic Whiskers Formed by Secondary Heat Treatment of Powdered Wood Charcoal and Their Optical and Magnetic Features
Yukie SAITO and Takanori ARIMA
Abstract:Cone-shaped graphitic whiskers were formed by secondary heat treatment of powdered wood charcoal loaded with SiC following heat treatment at 2500. As the formation mainly occurred outside the cell wall, microscopic observation was possible without great difficulty. As the result, the following unique characters were recognized: (1) By optical polarization microscopy on reflection mode, periodical structure in the direction perpendicular to the whisker axis was observed on the whisker surface. Considering these findings together with those of electron microscopy, wound carbon nanotube-like surface structure was suggested. (2) Whisker suspended in water was oriented with the whisker axis perpendicular to the magnetic field. These features were well explained by the highly ordered structure of the whisker showing stack of hexagonal carbon layers arranged as cone. Key Words:Wood charcoal, Vapor grown carbon, Electron microscopy, Optical anisotropy, Magnetic field orientation