The Structure of Black Carbon

Abstract

This paper is concerned with the structure of extremely small crystallites of carbon deposited upon silica by the pyrolysis of methane. Electron diffraction patterns have been obtained from more than 100 carbon films, from some by the reflection method, and from others by transmission after removing the films from their supports with hydrofluoric acid. In some of the specimens the individual crystallites are strongly oriented and reflection patterns obtained from these are approximations to rotation patterns from single crystals. From these patterns we have concluded that the films are made up of pseudo‐crystals in each of which the carbon atoms are hexagonally arranged in planes as they are in graphite, but successive parallel atomic layers are displaced so that no regularities exist other than the uniform separation of the planes and the regular arrangement of atoms in each of them.