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Indexed by:期刊论文

Date of Publication:2017-09-01

Journal:JOURNAL OF NUCLEAR MATERIALS

Included Journals:SCIE、EI、Scopus

Volume:493

Page Number:442-447

ISSN No.:0022-3115

Key Words:Tin; Tungsten; Ion implantation; Point defects; Chemical shift

Abstract:Prior to the practical application of liquid metals as facing material for fusion reactor, the nature of the interaction layer between liquid metal and tungsten substrate should be studied deeply. In the present work, by means of ion implantation technique using a metal vapor vacuum arc source (MEVVA), Sn ions were injected into a W matrix and a W-Sn modified layer was prepared. The chemical state, crystal structure and nano-indentation hardness of the modified layer were investigated and characterized with the use of X-ray photoelectron spectroscopy (XPS), an X-ray diffractometer (XRD) and a nano-indentor. The results indicate that, after the injection of Sn ions into the W matrix, Sn atoms interacted intensively with W, leading to the generation of a large number of point defects (such as vacancies and self-interstitial atoms) and the decrease of average grain size from 16.7 to 11.9 nm. Additionally, chemical shifts appeared, i.e., the binding energy values of W 4f(7/2), W 4f(5/2), W 5p(3/2) and W 4p(1/2) in the modified layer was reduced by 0.3 eV, 0.3 eV, 0.4 eV, 1-1.4 eV, respectively. The binding energy values of Sn 3d(5/2) and Sn 3d(3/2) decreased, with a chemical shift of 0.6-0.7 eV and 0.1-0.3 eV, respectively. The nano-indentation hardness of the modified layer was enhanced; specifically, when the indentation depth was 26.3 nm, the hardness reached a peak value of 13.8 GPa. In the modified layer, the surface chemical states are quite complex, mainly including SnO, WO3, SnO2 and WC. (C) 2017 Elsevier B.V. All rights reserved.