NIIgraphite

Moscow, Russia

NIIgraphite

Moscow, Russia

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Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Virgiliev Y.S.,NIIgraphite | Mashkova E.S.,Moscow State University | And 2 more authors.
Journal of Surface Investigation | Year: 2013

The results of experimentally investigating the sputtering and erosion of the basal plane of highly oriented pyrographite UPV-1T under irradiation with 30-keV Ar+ in the range from room temperature to 400°C are presented. It has been found that ion-induced surface-relief evolution at higher temperatures results in a two-fold increase in the sputtering yield (Y = 2) in comparison with sputtering of a surface with a nanosized relief at temperatures less than that of the texture transition Tt ≈ 150°C. Sputtering simulation using the OKSANA code for a surface with a sinusoidal nanorelief, which reflects the instability of the basal plane of UPV-1T under ion irradiation, permits to estimate the ratio of the amplitude to the relief period at T & Tt. © 2013 Pleiades Publishing, Ltd.


Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Mashkova E.S.,Moscow State University | Virgiliev Y.S.,NIIgraphite
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2011

The ion-induced erosion, determining by sputtering yield Y and surface evolution including structure and morphology changes of the modified surface layers, of two commercial carbon fiber composites (CFC) with different reinforcement - KUP-VM (1D) and Desna 4 (4D) have been studied under 30 keV Ar+ high fluence (t ∼ 1018-1020 ion/cm 2) irradiation in the temperature range from room temperature to 400 °C. Ion-induced erosion results in the changes of carbon fiber structure which depend on temperature and ion fluence. Monitoring of ion-induced structural changes using the temperature dependence of ion-induced electron emission yield has shown that for Desna 4 and KUP-VM at dynamic annealing temperature Ta ≈ 170 ° the transition takes place from disordering at T < Ta to recrystallization at T > T a. The annealing temperature Ta is close to the one for polycrystalline graphites. Microscopy analysis has shown that at temperatures < Ta the etching of the fibers results in a formation of trough-like longitudinal cavities and hillocks. Irradiation at temperatures T > Ta leads to a crimped structure with the ribs perpendicular to fiber axis. After further sputtering of the crimps the fiber morphology is transformed to an isotropic globular structure. As a result the sputtering yield decreases for Desna 4 more than twice. This value is almost equal to that for KUP-VM, Desna 4, polycrystalline graphites and glassy carbons at room temperature. © 2010 Elsevier B.V. All rights reserved.


Avilkina V.S.,Moscow State University | Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Virgiliev Y.S.,NIIgraphite | And 3 more authors.
Journal of Surface Investigation | Year: 2011

Analysis of the comparative influence of complete amorphization of a polycrystalline graphite surface layer and radiation-induced disordering of highly oriented pyrolytic graphite UPV-1T on the character of temperature dependences of the ion-electron emission yield under high-dose (1018-1019 ion/cm2) 30 keV Ar+ ion irradiation has been carried out. © 2011 Pleiades Publishing, Ltd.


Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Mashkova E.S.,Moscow State University | Shemukhin A.A.,Moscow State University | And 2 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2015

The results of the experimental study of sputtering and erosion of the basal plane of HOPG under irradiation with 30-keV Ar+ in the range from RT to 400 °C are presented. It has been found that developed at elevated (≥250 °C) temperatures needle-like microscopic relief results in twofold sputtering yield increase (Y 2) in comparison with sputtering of a surface with an etch pits microscopic relief at the temperatures less than the ion-induced texture transition temperature Tt 150 °C. The effects of ion-induced graphite relief on high-dose sputtering have been studied using binary-collision computer simulation. The relief was modeled as a sine function surface along two mutually perpendicular surface axes. The simulation has shown that at some parameters of the relief the essential part of the bombarding ions undergoes inclined incidence on the walls of surface hillocks, which increases the density of ion-atom collisions near the surface and, correspondingly, the ejection of atoms. This effect leads to non-monotonic behavior of the sputtering yield on the relief aspect ratio (amplitude/period). The sputtering yield decreases upon reaching the maximum at aspect ratio of 4, and becomes lower than that for a flat surface. The simulation permits to estimate the relation of amplitude to period of relief at T < Tt. © 2014 Elsevier B.V.


Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Mashkova E.S.,Moscow State University | Virgiliev Yu.S.,NIIgraphite
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2013

The temperature dependences of ion-induced electron emission yield γ (T) under 10-30 keV Ar+ high-fluence ion irradiation of glassy carbon SU-2500 at normal ion incidence have been analyzed to trace the structure and morphology changes depending on the irradiation temperature and the level of radiation damage ν measured in dpa (displacements per atom). It has been found that high fluence ion irradiation can result in changes of pristine structure of glassy carbon to amorphous structure at relatively low temperatures (T ≤ 100°C) and to ordering till polycrystalline graphite structure at elevated temperatures (T ≥ 250°C) The amorphization at room temperature is started at the mean radiation damage level 〈m〉 ∼ 50 dpa and finished at 〈m〉 ≈ 75 dpa. The graphitization at T > 250°C begins at 〈m〉 ≈ 75 dpa. © 2013 Elsevier B.V. All rights reserved.


Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Mashkova E.S.,Moscow State University | Virgiliev Yu.S.,NIIgraphite
Journal of Spacecraft and Rockets | Year: 2011

The sputtering, morphology, and crystalline structure modification of highly oriented pyrolytic graphite, polycrystalline graphites, glassy carbons, and the carbon-fiber composite materials under high-fluence (10 18-10 19 ion/cm 2) 30 keV N + 2 and Ar + ions at the incidence angles from 0° (normal incidence) to 80° from room temperature till elevated temperatures (∼400°C) have been studied. The radiation damage influence on the erosion regularities is discussed. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc.


Avilkina V.S.,Moscow State University | Andrianova N.N.,Moscow State University | Borisov A.M.,Moscow State University | Virgiliev Y.S.,NIIgraphite | And 2 more authors.
Journal of Surface Investigation | Year: 2012

The results of experimental study and computer simulation of SG-P-0. 1 carbon-ceramic composite sputtering under 30 keV Ar + ion irradiation at normal incidence are presented. A comparison with the simulation data shows that taking into account the nanometric wave-like relief well describes an approximately threefold increase in the sputtering yield observed in the experiment in comparison to the smooth surface calculation. © 2012 Pleiades Publishing, Ltd.

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