Observations of Crystal Structure And Particle Shape in Electron Micrographs of Several Carbon Blacks

As a sequel to an earlier paper, electron micrographs are shown which demonstrate crystal structure directly in so‐called amorphous carbon blacks. The crystalline particles of such a substance have a smaller mean size than the amorphous particles in the total distribution. The effect of variable particle shape upon such things as mean particle diameter and specific surface calculations is pointed out. It is suggested from all the experimental evidence, including electron and x‐ray diffraction data, that the crystal particles are small graphitic units, and that the graphitic nature of the carbon black is a surface rather than a volume phenomenon. The presence of the crystalline component in a carbon black distribution seems to be an intrinsic property of acetylene black made at high temperature.