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

详细信息    查看全文

• 作者：Shanmin Wang ; Xiaohui Yu ; Zhijun Lin ; Ruifeng Zhang ; Duanwei He ; Jiaqian Qin ; Jinlong Zhu ; Jiantao Han ; Lin Wang ; Ho-kwang Mao ; Jianzhong Zhang ; Yusheng Zhao
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：24
• 期：15
• 页码：3023-3028
• 全文大小：372K
• 年卷期：v.24,no.15(August 14, 2012)
• ISSN：1520-5002

文摘

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鈥揘 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.

Keywords:

hors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=tungsten+nitride&qsSearchArea=searchText">tungsten nitride; hors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=high%5C-pressure+synthesis&qsSearchArea=searchText">high-pressure synthesis; hors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=ion+exchange&qsSearchArea=searchText">ion exchange