Structures and physical properties of superhard and ultrahard 3D polymerized fullerites created from solid C60 by high pressure high temperature treatment

Бланк, В. Д.; Буга, С. Г.; Serebryanaya, N. R.; Dubitsky, G.A.; Маврин, Б. Н.; Popov, M.; Баграмов, Р. Х.; Prokhorov, V. M.; Sulyanov, S. N.; Kulnitskiy, B.A.; Tatyanin, Ye.V.

doi:10.1016/s0008-6223(98)00065-7

Cited by 60 publications

(26 citation statements)

References 8 publications

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“…13 Although only few peaks have been found in x-ray diffraction ͑XRD͒ of the superhard phase, several attempts have been made to determine the structure. 14,15 A recent XRD study of a sample prepared at 13 GPa and 820 K using synchrotron radiation revealed Debye-Sherrer ellipses instead of normal rings due to strong internal stresses. 16 The appearance of these ellipses in the XRD of quenched samples has been interpreted as evidence for three-dimensional polymerization.…”

Section: Introductionmentioning

confidence: 99%

In situx-ray diffraction study ofC60polymerization at high pressure and temperature

et al. 2002

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The C 60 polymerization was studied by x-ray diffraction in situ in the pressure range 13-18 GPa and at temperatures up to 830 K and nonhydrostatic conditions. Quenched samples were studied ex situ by Raman spectroscopy. The results of the high-pressure and high-temperature treatment are strongly dependent on the history of the sample and stress. An inaccurate increase of the pressure leads to the formation of internal stresses in the sample which gives elliptical Debye-Scherrer diffraction rings already at room temperature. During the subsequent heat treatment a soft amorphous phase is formed. At certain conditions no elliptical diffraction patterns were observed at 13 GPa and 830 K. Samples with a relatively low internal stress showed a transformation to a phase with decreased c-cell parameter compared to the known two-dimensional rhombohedral phase. The observed phase can be described as distorted cubic, but a better fit is achieved using a rhombohedral cell. It is suggested that this phase is a three-dimensional polymer with each C 60 molecule bonded to eight neighbors. This phase showed an increased hardness ͑about 37 GPa͒ and a Raman spectrum distinctly different from previously known polymeric phases.

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Section: Introductionmentioning

confidence: 99%

In situx-ray diffraction study ofC60polymerization at high pressure and temperature

et al. 2002

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“…So far, three crystalline phases and some amorphous phases of polymerized fullerenes were synthesized. One of the amorphous phases have hardness high enough to scratch the (111) face of diamond [4][5][6][7].…”

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confidence: 99%

XRD and TEM study of high pressure treated single-walled carbon nanotubes and C60-peapods

Kawasaki

Matsuoka

Yokomae

et al. 2005

Carbon

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In situ synchrotron X-ray diffraction measurements of single-walled carbon nanotube and C 60 -peapod samples under high pressures up to 13 GPa and at high temperature were carried out. Anisotropical shrinkages of their bundle 2-dimensional lattices by compression at room temperature were observed. It was found that the lattices recover original forms reversibly upon pressure release. It was also found Preprint submitted to Elsevier Science 19 August 2004that irreversible phase transformations occur by raising temperature at the highest pressure. The high-pressure and high-temperature treated samples were examined by X-ray diffraction, transmission electron microscope, and Raman measurements.It was indicated by transmission electron microscope observation that hexagonal diamond is able to be synthesized by high pressure and high temperature treatment of C 60 -peapods.

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“…[1][2][3][4][5][6] Unfortunately, it is difficult to prove that a given phase exceeds diamond hardness. A common problem for all recent claims is an insufficient amount of material for hardness testing.…”

Section: Crystal Phases Harder Than Diamondmentioning

confidence: 99%

“…The extraordinary success of high-pressure/high-temperature (HP/HT) synthesis of diamond, cubic boron nitride, and stishovite (a dense form of SiO 2 ) suggested consideration of new crystal phases with hardness exceeding that of diamond as a possibility. [1][2][3][4][5][6] Unfortunately, it is difficult to prove that a given phase exceeds diamond hardness. A common problem for all recent claims is an insufficient amount of material for hardness testing.…”

Section: Crystal Phases Harder Than Diamondmentioning

confidence: 99%

Stability of Silicon Carbonitride Phases

Badzian

2002

Journal of the American Ceramic Society

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Important hard phases are included in the quaternary compositional system Si-N-C-B. This paper reviews ternary amorphous and crystalline phases in the system Si-N-C and deliberates on the issue of stability of the binary C 3 N 4 , a hypothetical phase harder than diamond, and instability of nitrides in general. There is a tendency for nitrogen atoms to agglomerate and be released as nitrogen molecules. Stabilization of CN radicals can be achieved through ternary phases: carbonitrides metal-C-N. Ternary Si-N-C phases have been synthesized by pyrolysis of polyorganosilazanes, physical vapor deposition, and chemical vapor deposition. The crystalline ␣-Si 3 N 4 :C phase can incorporate about 6 at.% C and yields enhancement of hardness and wear resistance. Other crystalline phases contain more carbon, for example, Si 2 CN 4 .

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Structures and physical properties of superhard and ultrahard 3D polymerized fullerites created from solid C60 by high pressure high temperature treatment

Cited by 60 publications

References 8 publications

In situx-ray diffraction study ofC60polymerization at high pressure and temperature

In situx-ray diffraction study ofC60polymerization at high pressure and temperature

XRD and TEM study of high pressure treated single-walled carbon nanotubes and C60-peapods

Stability of Silicon Carbonitride Phases

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