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Nanoscience and Technology: An International Journal

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ISSN Druckformat: 2572-4258

ISSN Online: 2572-4266

The Impact Factor measures the average number of citations received in a particular year by papers published in the journal during the two preceding years. 2017 Journal Citation Reports (Clarivate Analytics, 2018) IF: 1.3 To calculate the five year Impact Factor, citations are counted in 2017 to the previous five years and divided by the source items published in the previous five years. 2017 Journal Citation Reports (Clarivate Analytics, 2018) 5-Year IF: 1.7 The Immediacy Index is the average number of times an article is cited in the year it is published. The journal Immediacy Index indicates how quickly articles in a journal are cited. Immediacy Index: 0.7 The Eigenfactor score, developed by Jevin West and Carl Bergstrom at the University of Washington, is a rating of the total importance of a scientific journal. Journals are rated according to the number of incoming citations, with citations from highly ranked journals weighted to make a larger contribution to the eigenfactor than those from poorly ranked journals. Eigenfactor: 0.00023 The Journal Citation Indicator (JCI) is a single measurement of the field-normalized citation impact of journals in the Web of Science Core Collection across disciplines. The key words here are that the metric is normalized and cross-disciplinary. JCI: 0.11 SJR: 0.244 SNIP: 0.521 CiteScore™:: 3.6 H-Index: 14

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STRUCTURE FORMATION AND CHANGES IN THE REACTIVITY OF COMPOSITE GRANULES OF THE Nb−Si SYSTEM IN MECHANICAL ACTIVATION

Volumen 5, Ausgabe 3, 2014, pp. 213-221
DOI: 10.1615/NanomechanicsSciTechnolIntJ.v5.i3.50
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ABSTRAKT

The basic laws governing the structure formation and changes in the activity of composite granules of the Nb-Si system in mechanical activation in order to reach maximum efficiency of the subsequent synthesis of niobium silicides have been considered. The mechanical activation of composite granules was performed using a Retsch PM 400 planetary mill. The activity, characterizing integrally the energy intensity and the reactivity of composite granules, was evaluated by the velocity of propagation of the front of the linearly organized reaction of niobium silicides synthesis. The structure was investigated with the aid of a light and an electronic microscope, as well as an X-ray diffractometer. Typical structures of composite granules and the charts of changes in their activity as a function of processing time are presented. The initial growth of activity is conditioned by the increasing uniformity of distribution and enlargement of the contact area of niobium and silicon, decrease in the share of niobium defect regions, not containing silicon, and accumulation of internal energy related to the increasing imperfection of the crystalline structure of the components. A decrease in the activity after reaching the maximum is related to chemical interaction of the components in microvolumes of composite granules and relaxation of the accumulated energy. We identified the structuring role of silicon: its nanosized particles, having superhigh conglomeration capacity, capture and bond the niobium particles, thus ensuring the formation of structures of composite granules. The regions of niobium that are free from silicon represent the basic structural defect of granules. An increase in the mechanical activation time results in thinning of the niobium particles and silicon layers, thus generating a more homogeneous structure and reducing the relative volume of defect regions. The optimal time of silicon preprocessing was found to be 60 min. The Nb5Si3 composite granules have the maximum activity after 180 min of mechanical activation, while Nb3Si granules after 260 min.

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