Structure and microhardness of low pressure polymerized fullerite C₆₀

Structure and microhardness of low pressure polymerized fullerite C₆₀

We have carried out low-temperature x-ray diffraction studies on C₆₀ fullerite polymerized by low quasi-hydrostatic pressure of 1.1 GPa at T = 563 K. It is established that at room temperature in freshly prepared samples three phases mainly coexist, viz. a compressed cubic phase with the lattice par...

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Datum:1998
Hauptverfasser: Isakina, A.P., Lubenets, S.V., Natsik, V.D., Prokhvatilov, A.I., Strzhemechny, M.A., Fomenko, L.S., Aksenova, N.A., Soldatov, A.V.
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Sprache:English
Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 1998
Schriftenreihe:Физика низких температур
Schlagworte:
Динамика кристаллической решетки
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/176694
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Zitieren:Structure and microhardness of low pressure polymerized fullerite C₆₀ / A.P. Isakina, S.V. Lubenets, V.D. Natsik, A.I. Prokhvatilov, M.A. Strzhemechny, L.S. Fomenko, N.A. Aksenova, A.V. Soldatov // Физика низких температур. — 1998. — Т. 24, № 12. — С. 1192-1201. — Бібліогр.: 32 назв. — англ.

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spelling nasplib_isofts_kiev_ua-123456789-1766942025-02-09T10:37:34Z Structure and microhardness of low pressure polymerized fullerite C₆₀ Isakina, A.P. Lubenets, S.V. Natsik, V.D. Prokhvatilov, A.I. Strzhemechny, M.A. Fomenko, L.S. Aksenova, N.A. Soldatov, A.V. Динамика кристаллической решетки We have carried out low-temperature x-ray diffraction studies on C₆₀ fullerite polymerized by low quasi-hydrostatic pressure of 1.1 GPa at T = 563 K. It is established that at room temperature in freshly prepared samples three phases mainly coexist, viz. a compressed cubic phase with the lattice parameter a = 13.94 Angstrem , an orthorhombic O` phase with the lattice parameters a = 9.12 Angstrem , b = 9.82 Angstrem, c = 14.60 Angstrem, and a rhombohedral phase of symmetry R3m with the parameters a = 9.20 Angstrem and c = 24.27Angstrem. Mechanical grinding or annealing at 573 K entails depolymerization of sintered samples and restoration of the fcc structure of pristine C₆₀. During annealing in air, intercalation of fullerite lattice by oxygen molecules occurs as well as a substantial amount of some new phase is formed, most probably with tetragonal symmetry, the chemical composition and structure of which have not been determined. The microhardness of polymerized C₆₀ is higher than that of single crystal samples roughly four-fold at room temperature and by a factor of 2.6 at liquid nitrogen temperature. Analysis shows that polymerization and grain boundaries give contributions to the microhardness of sintered samples but we did not succeed in separating these two contributions. The temperature dependence of the microhardness of polymerized samples exhibits a jump in the vicinity of 260 K, where pristine C₆₀ fullerite undergoes the fcc-sc phase transition. We think that this jump is due to a partial destruction of the polymerized state under indentor as a result of shear straining in inhomogeneous stress fields. Annealing of polymerized C₆₀ at a temperature of 573 K, which restores the fcc phase, leads to a considerable decrease in microhardness, the hardness "jump" near the fcc-sc transition extends in temperature and shifts to lower temperatures. The authors are sincerely indebted to Prof. B. Sundqvist for kindly reading the manuscript and giving several important remarks that substantially improved this paper. The authors, S.V.L., V.D.N., and L.S.F., wish to thank the Swiss National Science Foundation for the partial financial support of this work through a program CEEC.NIS, project No 7UKPJ04864, A. V. S. acknowledges the financial support of the Swedish Natural Sciences Research Council (NFR). 1998 Article Structure and microhardness of low pressure polymerized fullerite C₆₀ / A.P. Isakina, S.V. Lubenets, V.D. Natsik, A.I. Prokhvatilov, M.A. Strzhemechny, L.S. Fomenko, N.A. Aksenova, A.V. Soldatov // Физика низких температур. — 1998. — Т. 24, № 12. — С. 1192-1201. — Бібліогр.: 32 назв. — англ. 0132-6414 PACS: 61.10.-i, 64.70.Kb, 64.70.Pf, 62.20.Fe https://nasplib.isofts.kiev.ua/handle/123456789/176694 en Физика низких температур application/pdf Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Динамика кристаллической решетки
Динамика кристаллической решетки
spellingShingle Динамика кристаллической решетки
Динамика кристаллической решетки
Isakina, A.P.
Lubenets, S.V.
Natsik, V.D.
Prokhvatilov, A.I.
Strzhemechny, M.A.
Fomenko, L.S.
Aksenova, N.A.
Soldatov, A.V.
Structure and microhardness of low pressure polymerized fullerite C₆₀
Физика низких температур
description We have carried out low-temperature x-ray diffraction studies on C₆₀ fullerite polymerized by low quasi-hydrostatic pressure of 1.1 GPa at T = 563 K. It is established that at room temperature in freshly prepared samples three phases mainly coexist, viz. a compressed cubic phase with the lattice parameter a = 13.94 Angstrem , an orthorhombic O` phase with the lattice parameters a = 9.12 Angstrem , b = 9.82 Angstrem, c = 14.60 Angstrem, and a rhombohedral phase of symmetry R3m with the parameters a = 9.20 Angstrem and c = 24.27Angstrem. Mechanical grinding or annealing at 573 K entails depolymerization of sintered samples and restoration of the fcc structure of pristine C₆₀. During annealing in air, intercalation of fullerite lattice by oxygen molecules occurs as well as a substantial amount of some new phase is formed, most probably with tetragonal symmetry, the chemical composition and structure of which have not been determined. The microhardness of polymerized C₆₀ is higher than that of single crystal samples roughly four-fold at room temperature and by a factor of 2.6 at liquid nitrogen temperature. Analysis shows that polymerization and grain boundaries give contributions to the microhardness of sintered samples but we did not succeed in separating these two contributions. The temperature dependence of the microhardness of polymerized samples exhibits a jump in the vicinity of 260 K, where pristine C₆₀ fullerite undergoes the fcc-sc phase transition. We think that this jump is due to a partial destruction of the polymerized state under indentor as a result of shear straining in inhomogeneous stress fields. Annealing of polymerized C₆₀ at a temperature of 573 K, which restores the fcc phase, leads to a considerable decrease in microhardness, the hardness "jump" near the fcc-sc transition extends in temperature and shifts to lower temperatures.
format Article
author Isakina, A.P.
Lubenets, S.V.
Natsik, V.D.
Prokhvatilov, A.I.
Strzhemechny, M.A.
Fomenko, L.S.
Aksenova, N.A.
Soldatov, A.V.
author_facet Isakina, A.P.
Lubenets, S.V.
Natsik, V.D.
Prokhvatilov, A.I.
Strzhemechny, M.A.
Fomenko, L.S.
Aksenova, N.A.
Soldatov, A.V.
author_sort Isakina, A.P.
title Structure and microhardness of low pressure polymerized fullerite C₆₀
title_short Structure and microhardness of low pressure polymerized fullerite C₆₀
title_full Structure and microhardness of low pressure polymerized fullerite C₆₀
title_fullStr Structure and microhardness of low pressure polymerized fullerite C₆₀
title_full_unstemmed Structure and microhardness of low pressure polymerized fullerite C₆₀
title_sort structure and microhardness of low pressure polymerized fullerite c₆₀
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
publishDate 1998
topic_facet Динамика кристаллической решетки
url https://nasplib.isofts.kiev.ua/handle/123456789/176694
citation_txt Structure and microhardness of low pressure polymerized fullerite C₆₀ / A.P. Isakina, S.V. Lubenets, V.D. Natsik, A.I. Prokhvatilov, M.A. Strzhemechny, L.S. Fomenko, N.A. Aksenova, A.V. Soldatov // Физика низких температур. — 1998. — Т. 24, № 12. — С. 1192-1201. — Бібліогр.: 32 назв. — англ.
series Физика низких температур
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first_indexed 2025-11-25T20:42:09Z
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