Metastable crystalline and amorphous carbon phases obtained from fullerite<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>by high-pressure–high-temperature treatment

Бражкин, В. В.; Lyapin, A. G.; Попова, С. В.; Волошин, Р. Н.; Antonov, Yu. V.; Lyapin, S. G.; Kluev, Yu. A.; Naletov, A. M.; Melnik, N. N.

doi:10.1103/physrevb.56.11465

Cited by 74 publications

(44 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Amorphous and nanocrystalline diamond materials have been successfully synthesized from graphite and soot [49], carbon nanotubes [39], fullerite C 60 [50]. The nano-size of the grains has been achieved through direct catalyst-free transformations of carbon materials into diamond with a low grain growth rate and a high nucleation frequency.…”

Section: Superhard Materials: More Equal Than Othersmentioning

confidence: 99%

“…Such single crystals have the Knoop hardness of 145 GPa, which is by 1.5 times greater than the values for ordinary natural diamonds. These impurity-free defect-free diamonds have already found application as indenters for hardness testing machines [48].Amorphous and nanocrystalline diamond materials have been successfully synthesized from graphite and soot [49], carbon nanotubes [39], fullerite C 60 [50]. The nano-size of the grains has been achieved through direct catalyst-free transformations of carbon materials into diamond with a low grain growth rate and a high nucleation frequency.…”

mentioning

confidence: 99%

See 1 more Smart Citation

High-pressure synthesized materials: treasures and hints

Бражкин

2007

High Pressure Research

Self Cite

105

View full text Add to dashboard Cite

The present review covers the production of new materials under high pressures. A primary limitation on the use of pressures higher than 1 GPa is a small volume and mass of a produced material. Therefore, despite an extremely wide range of new high-pressure synthesized substances with unique properties, synthesis on an commercial scale is applied up to now only to obtain superhard materials, this real treasure of today's industry. At the same time, high-pressure experiments often give material scientists a hint at what new intriguing substances can exist in principle. This is true for new superhard, semiconducting, magnetic, superconducting and optical materials already synthesized under pressure, and as well as for a large number of hypothetic new polymers from low-Z elements. Many of new materials, including the above polymers, may exist in the metastable form at normal pressure at sufficiently high temperatures.Keywords: high pressure, materials synthesis, metastable phases 1 IntroductionThe synthesis of materials under high pressure is a vast area of physics, chemistry and engineering. Should you browse the Internet to search "high pressure synthesis", the web search engines, for example, Google, would respond with over 10 mln links, making it absolutely impossible to write any comprehensive review on this topic. For this same reason, neither it is possible to list all relevant references. The purpose of this paper is to present the author's personal view on the state of art and prospects of the production of new materials by using highpressure synthesis, and to complement already existing reviews, for example [1,2]. It should be noted that a number of publications, for example [2], discuss a comparatively narrow range of materials synthesized under pressure. Other publications, for example [1], also focus on anomalous properties of materials in a strongly compressed state, although most of materials with such properties cannot be retained at normal pressure, hence, they are not directly related to the subject under consideration. In addition, the behavior of materials in a strongly compressed state has also been extensively covered in scientific literature (for example, see [3]).For physicists, the history of a high-pressure research is first of all associated with P.W. Bridgman, a 1946 Nobel Prize Laureate "for the invention of an apparatus to produce extremely high pressures, and for the discoveries he made therewith in the field of high pressure physics". Nowadays high-pressure synthesis of new materials is primarily associated with a successful synthesis of superhard materials -diamond and cubic boron nitride -in the second half of the 20 th century. At the same time, the pressures 1 -10 3 MPa have been already in use for more than a century in chemistry for the industrial production of materials. What's more, the development of relevant engineering procedures has been more than once rewarded with a Nobel Prize in chemistry. In 1918, F. Haber won the Nobel Prize "for the synthesis of ammonia from its el...

show abstract

Section: Superhard Materials: More Equal Than Othersmentioning

confidence: 99%

mentioning

confidence: 99%

High-pressure synthesized materials: treasures and hints

Бражкин

2007

High Pressure Research

Self Cite

105

View full text Add to dashboard Cite

show abstract

“…5,6 The polymerization is attained by the so-called ͓2ϩ2͔ cycloaddition mechanism via the formation of the fourmembered rings between adjacent fullerene molecules. 8,9 The most interesting results are those which led to the threedimensional polymerization of fullerite, 10,11 a first stage to the synthesis of ultrahard phases. 12 Recently, Okada et al 13 have shown theoretically the possibility of three-dimensional ͑3D͒ polymerization of fullerite using the density-functional theory.…”

Section: Introductionmentioning

confidence: 99%

Pressure-induced phase in tetragonal two-dimensional polymericC60

et al. 2001

View full text Add to dashboard Cite

The behavior of the phonon modes of the tetragonal phase of the two-dimensional polymerized C 60 has been studied as a function of pressure, up to 27.5 GPa, at room temperature by means of Raman spectroscopy. Gradual transformation of the material to a new phase was observed in the pressure region 19.0-21.0 GPa. As a result of this phase transformation dramatic changes in the Raman spectrum have been recorded. Namely, the total number of bands was reduced and a number of very strong peaks appeared. The Raman spectrum characteristics provide strong indication that the fullerene molecular cage is retained and therefore the highpressure phase may be related to a three-dimensionally polymerized C 60 phase. The high-pressure phase remains stable upon pressure decrease from 27.5 down to 9 GPa. Further release of pressure leads to the destruction of this high-pressure phase to a highly disordered structure whose broad features in the Raman spectrum resemble those of amorphous carbon.

show abstract

“…Indeed, in early experiments very hard and stiff materials were synthesised (stable under ambient conditions) by compressing fullerite under high pressure [6]. Subsequently, these phases have been characterised experimentally by determining their structural, mechanical, and optical properties [7,8,9,10,11,12,13,14,15] revealing a plethora of ordered (polymerised fullerenes) and disordered (amorphous) carbon phases (see [7] for a review).Based on electron diffraction experiments, shockcompressed fullerite [16], has been conjectured to be a new form of amorphous diamond exhibiting IRO [7]. Furthermore, it has been argued that the mechanical properties are determined by remnants of (partially) intact fullerene cages distinguishing these phases from tetrahedrally coordinated amorphous carbon (ta-C) produced by ion-beam techniques.…”

mentioning

confidence: 99%

Understanding of the Phase Transformation from Fullerite to Amorphous Carbon at the Microscopic Level

et al. 2005

View full text Add to dashboard Cite

We have studied the shock-induced phase transition from fullerite to a dense amorphous carbon phase by tight-binding molecular dynamics. For increasing hydrostatic pressures P , the C60-cages are found to polymerise at P < 10 GPa, to break at P ∼ 40GPa and to slowly collapse further at P > 60 GPa. By contrast, in the presence of additional shear stresses, the cages are destroyed at much lower pressures (P < 30 GPa). We explain this fact in terms of a continuum model, the snapthrough instability of a spherical shell. Surprisingly, the relaxed high-density structures display no intermediate-range order. The extraordinary elastic properties of the molecular cage of C 60 have inspired many to speculate about new carbon modifications with extraordinary mechanical performance [5]. Indeed, in early experiments very hard and stiff materials were synthesised (stable under ambient conditions) by compressing fullerite under high pressure [6]. Subsequently, these phases have been characterised experimentally by determining their structural, mechanical, and optical properties [7,8,9,10,11,12,13,14,15] revealing a plethora of ordered (polymerised fullerenes) and disordered (amorphous) carbon phases (see [7] for a review).Based on electron diffraction experiments, shockcompressed fullerite [16], has been conjectured to be a new form of amorphous diamond exhibiting IRO [7]. Furthermore, it has been argued that the mechanical properties are determined by remnants of (partially) intact fullerene cages distinguishing these phases from tetrahedrally coordinated amorphous carbon (ta-C) produced by ion-beam techniques.However, up to now, conjectures concerning the structural properties are based on indirect information; neither the process of formation of such structures nor the nature of the proposed intermediate range order is understood microscopically. Pioneering molecular-dynamics (MD) simulations have shown that subjecting fullerite to high pressure and high temperatures may give rise to a dense amorphous phase [17]. However, the sample in [17] had to be compressed to very high densities (4.4 g/cm 3 at T = 2500K) corresponding to pressures exceeding 100GPa, far beyond any experimentally obtainable conditions. Empirically, the transition from fullerite to amorphous carbon occurs in the range of 10 − 30 GPa, depending on the speed of compression and on temperature (room temperature in [6] and approximately 2000K in shock experiments [7,16]). How may this contradiction be resolved? There are indications that shear stress may play a role in the destabilisation of the cages [6]. However, at present it is not known which microscopic processes cause the transition from fullerite to amorphous carbon. There is thus a pressing need for a theoretical understanding of the exact microscopic mechanisms occurring during this phase transition. To which extent is a macroscopic picture of a rapidly imploding spherical shell appropriate? Is shear important? How strong is the dependence of the final structural properties on the details of the comp...

show abstract

Metastable crystalline and amorphous carbon phases obtained from fulleriteC60by high-pressure–high-temperature treatment

Cited by 74 publications

References 39 publications

High-pressure synthesized materials: treasures and hints

High-pressure synthesized materials: treasures and hints

Pressure-induced phase in tetragonal two-dimensional polymericC60

Understanding of the Phase Transformation from Fullerite to Amorphous Carbon at the Microscopic Level

Contact Info

Product

Resources

About