Structural and morphological transformations of carbon nanospheres during high-temperature, high-pressure processing

This paper presents analysis of structural changes in powders consisting of turbostratic carbon spheres with an average particle diameter of 250 and 25 nm after high-temperature, high-pressure processing at a pressure of 8 GPa. It has been shown that marked ordering of graphene sheets is observed at 1300°C and actively proceeds at higher temperatures. The major morphological species in the samples after processing is slabs of graphene sheets, and three-dimensional structural perfection is higher at the smaller particle size. Using high-resolution electron microscopy, samples of this powder were shown to contain diamond nanocrystallites.