Low-temperature microhardness of Xe-intercalated fullerite C60

Fomenko, L. S.; Lubenets, S. V.; Нацик, В. Д.; Cassidy, David J.; Gadd, G. E.; Moricca, S.; Sundqvist, Bertil

doi:10.1063/1.1925374

Cited by 5 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A typical HIP application is illustrated [4] by the intercalation of fullerite by inert gases such as Ar, Kr, and Xe where pressures of 170-220 MPa and temperatures of 200-500°C were used to produce intercalates Ar 1.0 C 60 , Kr 0.9 C 60 , and Xe 0.66 C 60 . Other applications of the HIP method may be found in a number of publications [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. In this method, temperature and pressure cannot substantially exceed the values given above because an increase in pressure results in fullerene polymerization while an increase in temperature leads to reactions with small reactive species such as oxygen.…”

Section: Introductionmentioning

confidence: 96%

Synthesis and properties of C60 fullerite intercalated by acetylene

Shul’ga¹,

Мартыненко²,

Баскаков³

et al. 2009

Chemical Physics Letters

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 96%

Synthesis and properties of C60 fullerite intercalated by acetylene

Shul’ga¹,

Мартыненко²,

Баскаков³

et al. 2009

Chemical Physics Letters

View full text Add to dashboard Cite

On the polyamorphism of fullerite-based orientational glasses

Aleksandrovskii

Bakaı̆

Cassidy

et al. 2005

Low Temperature Physics

View full text Add to dashboard Cite

The dilatometric investigation in the temperature range of 2-28K shows that a first-order polyamorphous transition occurs in the orientational glasses based on C60 doped with H2, D2 and Xe. A polyamorphous transition was also detected in C60 doped with Kr and He. It is observed that the hysteresis of thermal expansion caused by the polyamorphous transition (and, hence, the transition temperature) is essentially dependent on the type of doping gas. Both positive and negative contributions to the thermal expansion were observed in the low temperature phase of the glasses. The relaxation time of the negative contribution occurs to be much longer than that of the positive contribution. The positive contribution is found to be due to phonon and libron modes, whilst the negative contribution is attributed to tunneling states of the C60 molecules. The characteristic time of the phase transformation from the low-T phase to the high-T phase has been found for the C60-H2 system at 12K. A theoretical model is proposed to interpret these observed phenomena. The theoretical model proposed, includes a consideration of the nature of polyamorphism in glasses, as well as the thermodynamics and kinetics of the transition. A model of non-interacting tunneling states is used to explain the negative contribution to the thermal expansion. The experimental data obtained is considered within the framework of the theoretical model. From the theoretical model the order of magnitude of the polyamorphous transition temperature has been estimated. It is found that the late stage of the polyamorphous transformation is described well by the Kolmogorov law with an exponent of n=1. At this stage of the transformation, the two-dimensional phase boundary moves along the normal, and the nucleation is not important.Comment: 29 pages, 14 figures, added references, corrected typo

show abstract

Hydrogen absorption and desorption kinetics in fullerite C60 single crystals. Low-temperature micromechanical and structural characteristics of the interstitial solid solution C60(H2)x

Fomenko

Lubenets

Нацик

et al. 2008

Low Temperature Physics

View full text Add to dashboard Cite

The microhardness HV and lattice parameter a of C60 single crystals are measured at room temperature as functions of the hydrogen saturation time t for several values of the saturation temperature (250, 300, and 350°C) at a fixed hydrogen pressure p=30atm. According to the measurements of HV and a, the kinetics of hydrogen absorption is described by a simple exponential law with a single, temperature-dependent characteristic time. In highly saturated samples the microhardness is 4 times greater than for the initial C60 crystal, while the lattice parameter is 0.2% larger. The temperature dependence of the microhardness HV and lattice parameter a of C60(H2)x crystals is investigated in the temperature interval 77–300K. The introduction of hydrogen lowers the temperature of the fcc–sc phase transition, and the transition becomes strongly broadened in temperature. The dependence of the microhardness of the saturated sample on the hold time in air at room temperature is described by the sum of two exponentials with different characteristic times. Kinetics of this kind is presumably due to two processes: desorption of hydrogen from the sample, which causes a decrease of the microhardness, and a simultaneous penetration of gaseous impurities into the sample from the surrounding air, which is accompanied by hardening. The influence of the H2 molecules on the characteristic of the intermolecular interaction in fullerite C60 is discussed and the intercalation-induced processes of dislocation slip and microfracture.

show abstract

Low-temperature microhardness of Xe-intercalated fullerite C60

Cited by 5 publications

References 17 publications

Synthesis and properties of C60 fullerite intercalated by acetylene

Synthesis and properties of C60 fullerite intercalated by acetylene

On the polyamorphism of fullerite-based orientational glasses

Hydrogen absorption and desorption kinetics in fullerite C60 single crystals. Low-temperature micromechanical and structural characteristics of the interstitial solid solution C60(H2)x

Contact Info

Product

Resources

About