Synthesis, Crystal Structure, and Elastic Properties of Novel Tungsten Nitrides

Among transition metal nitrides, tungsten nitrides possess unique and/or superior chemical, mechanical, and thermal properties. Preparation of these nitrides, however, is challenging because the incorporation of nitrogen into tungsten lattice is thermodynamically unfavorable at atmospheric pressure....

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Published inChemistry of materials Vol. 24; no. 15; pp. 3023 - 3028
Main Authors Wang, Shanmin, Yu, Xiaohui, Lin, Zhijun, Zhang, Ruifeng, He, Duanwei, Qin, Jiaqian, Zhu, Jinlong, Han, Jiantao, Wang, Lin, Mao, Ho-kwang, Zhang, Jianzhong, Zhao, Yusheng
Format Journal Article
LanguageEnglish
Published United States American Chemical Society 14.08.2012
Subjects
ATMOSPHERIC PRESSURE
CRYSTAL STRUCTURE
DEGASSING
ELASTICITY
ION EXCHANGE
MATERIALS
MATERIALS SCIENCE
NITRIDES
NITROGEN
PRESSURE RANGE MEGA PA 10-100
PRODUCTION
SYNTHESIS
THERMODYNAMIC PROPERTIES
THIN FILMS
TRANSITION ELEMENTS
TUNGSTEN
TUNGSTEN NITRIDES
high-pressure synthesis
tungsten nitride
ion exchange
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Summary:Among transition metal nitrides, tungsten nitrides possess unique and/or superior chemical, mechanical, and thermal properties. Preparation of these nitrides, however, is challenging because the incorporation of nitrogen into tungsten lattice is thermodynamically unfavorable at atmospheric pressure. To date, most materials in the W–N system are in the form of thin films produced by nonequilibrium processes and are often poorly crystallized, which severely limits their use in diverse technological applications. Here we report synthesis of tungsten nitrides through new approaches involving solid-state ion exchange and nitrogen degassing under pressure. We unveil a number of novel nitrides including hexagonal and rhombohedral W2N3. The final products are phase-pure and well-crystallized in bulk forms. For hexagonal W2N3, hexagonal WN, and cubic W3N4, they exhibit elastic properties rivaling or even exceeding cubic-BN. All four nitrides are prepared at a moderate pressure of 5 GPa, the lowest among high-pressure synthesis of transition metal nitrides, making it practically feasible for massive and industrial-scale production.
Bibliography:FOREIGN
ISSN:0897-4756
1520-5002
DOI:10.1021/cm301516w