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In this article, Ni-coated W powders were firstly prepared by a liquid-solid doping method combined with air calcination and hydrogen reduction. X-ray diffraction analysis, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and temperature programmed reduction analysis were carried out to investigate the nickel doping process in WO3 and its influence on the reduction behaviors of tungsten oxides. It reveals that after calcinations most Ni ions would occupy the lattice sites of host W ions and decrease the interplanar spacing of WO3. The latter is due to the promotion of oxygen vacancy generation within WO3 rather than the changes in ionic radius. After hydrogen reduction, the doped Ni atoms precipitate onto the surface of W particles as thin metallic coatings, whereby the size and morphology of reduced W particles are varied greatly with increasing Ni addition. The presence of Ni has also been found to lower the reduction barriers for WO3 by using first-principles calculation. Finally, W-Ni compacts were sintered at 1500 degrees C in hydrogen atmosphere and the accelerated densification phenomenon of W alloy upon Ni doping is discussed.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
ISSN: 0263-4368
Year: 2019
Volume: 78
Page: 296-302
3 . 6 0 0
JCR@2022
ESI Discipline: MATERIALS SCIENCE;
ESI HC Threshold:211
JCR Journal Grade:2
Cited Count:
WoS CC Cited Count: 6
SCOPUS Cited Count: 8
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 0