Hardness of covalent compounds:: Roles of metallic component and d valence electrons
Hardness of covalent compounds:: Roles of metallic component and d valence electrons
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共价化合物的硬度：金属成分和 d 价电子的作用
DOI：
10.1063/1.2956594
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发表时间：
2008-07-15
影响因子：
3.2
通讯作者：
Wang, Hui-Tian
中科院分区：
文献类型：
--
作者：
Guo, Xiaoju;Li, Lei;Wang, Hui-Tian
在详细分析化学键的基础上，我们给出了过渡金属碳化物和氮化物等以共价为主的晶体的维氏硬度表达式。硬度不仅取决于键的长度、键密度和键的离子性[F.M.Gao等人，Phys.莱特牧师。91,015502(2003年)]以及化合物晶体结构中键和轨道形式的金属性，所有这些参数都可以通过第一性原理计算来确定。用我们的公式计算的硬度与已知的单碳化物、过渡金属单氮化物和具有Th3P4结构的立方Zr3N4的实验值符合得很好。此外，我们还预测了最近预测的四方相BC3和四方相B2CN，以及最近合成的黄铁矿PtN_2和白铁矿OsN_2的维氏硬度。我们的方法为在过渡金属碳化物和氮化物中寻找超硬材料提供了一种有用的技术。
Based on the detailed analysis of chemical bonds, we present a Vickers hardness expression for the covalency-dominant crystals such as transition-metal carbides and nitrides. Hardness is dependent not only on bond length, bond density, and ionicity of bond [F. M. Gao et al., Phys. Rev. Lett. 91, 015502 (2003)] but also on the metallicity of bond and orbital form in the crystal structure of a compound, and all of these parameters can be determined by first-principles calculations. The calculated hardness using our expression has a good agreement with the experimental values for known monocarbides, mononitrides of transition metals, and cubic Zr3N4 with Th3P4 structure. In addition, we have predicted the Vickers hardness of the recently predicted tetragonal BC3 and tetragonal B2CN, and the recently synthesized pyrite PtN2 and marcasite OsN2. Our method offers one useful technique to search for superhard materials in transition-metal carbides and nitrides.