Bulk nanostructured carbon phases prepared from C60: approaching the 'ideal' hardness

New nanomaterials have been prepared by high-temperature treatment of fullerite C60 at moderate (0.1-1.5 GPa) pressures attainable for large-volume pressure apparatus. The structure, EELS spectra, Raman spectra, hardness and elastic moduli of these carbon substances have been studied. The materials have a high (90%) elastic recovery, fairly high hardness H~10-15 GPa and record values of the hardness-to-Young-modulus ratio H/E~0.22. The observed hardness is close to the 'ideal' limit, which is associated with the nanostructure of the materials. This structure represents a combination of interlinked curved fragments of C60 molecules and nanographite nuclei.