High-resolution TEM observations of isolated rhombohedral crystallites in graphite blocks

Graphite blocks produced from natural graphite flake have been studied by high-resolution transmission electron microscopy (HRTEM). Previously, the rhombohedral structure was widely considered as a mosaic distribution in a hexagonal host and was probably produced only by mechanical shear or milling. In present investigation, isolated rhombohedral crystallites have been detected in graphite blocks, in addition to the hexagonal host with mosaic distributions of the rhombohedral phase. This was confirmed not only by the inclined angle of about 12° between {10–11} planes and the [0 0 0 1] direction, but also the rhombohedral ABC… stacking of graphite basal planes based on the HRTEM image.