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

Abstract

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.

Electrical-contact properties of a composite material with a copper matrix reinforced by superelastic hard carbon

“…The experimental technique at high pressures was described in detail in [6]. The sample synthesis parameters correspond to the condi tions of collapse of fullerene molecules with the for mation of a hard carbon phase [7][8][9].…”

C60and C70pressure-and-temperature transformations into fullerene-related forms

“…The HIP treatment of carbon nano-materials is less described in the available literature, while there are reported facts of the new bulk nano-carbons that were synthesized by means of HPHT. Several research groups informed on the high-pressure (up to 15 GPa) synthesis of the polymer (1D, 2D, 3D) and amorphous states from the C 60 and C 70 fullerenes [7][8][9][10][11][12][13] that are very hard. Some extremely hard carbon forms were also obtained from the nanotubes [14], graphite [15], and glassy carbon [16] at pressures above 10 GPa.…”

Mechanical and electronic properties of diborides of transition 3d–5d metals from first principles: Toward search of novel ultra-incompressible and superhard materials

“…Preliminary evidences of new natural ultrahard carbon phases were discussed while studying carbonaceous areas in shocked meteorites [15]. Note also that over the past decade extensive efforts were devoted to finding of a broad family of new superhard materials based on nano-sized high-pressure polymeric phases of carbon fullerenes, nanotubes and nano-diamonds, see for example [16][17][18][19][20][21][22] and references therein. However, in the latter case the nano-scale size effects should be involved to explain the observed phenomena.…”