New crystalline and amorphous carbon modifications produced from fullerite at high pressure

First-principles calculation of the structure and elastic properties of a 3D-polymerized fullerite

“…27 Furthermore, our estimated hardness is in very good agreement with that reported by Brazhkin et al for polymerized fullerites of a similar density. 9 Our theoretical results, on the other hand, by no means supports the hypothesis that the orthorhombic structure proposed by Chernozatonskii et al 6 could account for the extremely high hardness and elastic moduli reported for samples of fullerene C 60 quenched from 13 GPa and 820 K. In fact, the reported hardness may be overestimated by the lack of an adequate treatment of the possible effect of elastic recovery on the experimental measurements. High hardness ͑45 GPa͒ and elastic recovery ͑85%͒ has been reported for sp 2 -rich carbon films.…”

“…Accordingly, claims regarding the anomalously high hardness and elastic moduli of the HP/HT polymerized phases of fullerene C 60 have been received with reserve by the scientific community. [8][9][10] Recently, the crystal structure of the superhard fullerite was proposed by Chernozatonskii et al, on the basis of an x-ray-diffraction analysis of samples quenched from 13 GPa and 820 K ͑Ref. 6͒.…”

Nanocrystalline diamond synthesized from C60

“…Since the first artificial diamonds were manufactured in the mid-1950s, various methods (ranging from direct solid-state transformation of graphite under static or shock pressure to chemical-vapour deposition) for diamond and DLC synthesis under variable pressure and temperature conditions have been explored, resulting in materials with properties approaching those of natural diamonds [1,3,[6][7][8][9][10][11][12]. Ultrafine diamonds with grain sizes of 5-10 nm were synthesised by explosives and may display excellent properties as surface coating for metals [9].…”

Formation ofsp3Bonding in Nanoindented Carbon Nanotubes and Graphite

“…In the last decade, many high-pressure experiments have revealed the fascinating phase transformation of fullerenes into superhard polymeric and disordered-amorphous carbon phases. The hardness sometimes can approach that of single-crystal diamond [3][4][5][6][7][8], even at room temperature [9,10]. On the other hand, in graphite subjected to high pressure up to 65 GPa at room temperature, no superhardness is found after the pressure is removed [10,11].…”