Volume 118, Number 4, May 2017
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||20 July 2017|
New multifunctional tungsten nitride with energetic N6 and extreme hardness predicted from first principles
1 College of Aeronautical Engineering, Binzhou University - Binzhou 256600, China
2 State Key Laboratory of Superhard Materials, Jilin University - Changchun 130012, China
3 Foreign Language School, Binzhou University - Binzhou 256600, China
4 Institute of Fluid Physics, Academy of Engineering Physics - Mianyang 621900, China
5 Department of Physics and Engineering Physics - University of Saskatchewan - Saskatoon, SK, S7N 5E2, Canada
6 Canadian Light Source - Saskatoon, SK, S7N 2V3, Canada
Received: 22 May 2017
Accepted: 27 June 2017
We report a new member to the family of tungsten nitrides, WN6, predicted from the structure search. Ground-state convex hull calculation reveals that crystalline WN6 is thermodynamically stable at pressures above 16 GPa, but remains dynamically stable at ambient conditions. The predicted high-pressure WN6 structure contains chaired rings isoelectronic to cyclo-hexasulfur (S6), which is unprecedented in nitrogen. In the unit all nitrogen atoms are singly bonded and therefore contain a high energy density. By means of efficiently packing the covalent-bonded species, WN6 is estimated to have extremely high Vickers hardness greater than 40 GPa at ambient conditions, placing it as one of the hardest materials. The present results reveal that WN6 may be used as a superhard material but simultaneously maintaining other desirable properties, which represents an interesting example of multifunctional materials.
PACS: 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects / 63.20.-e – Phonons in crystal lattices / 64.60.-i – General studies of phase transitions
© EPLA, 2017
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.