Novel compounds in the Zr-O system, their crystal structures and mechanical properties
Novel compounds in the Zr-O system, their crystal structures and mechanical properties
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Zr-O系新型化合物及其晶体结构和机械性能
DOI：
10.1039/c5cp02252e
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发表时间：
2015
影响因子：
3.3
通讯作者：
Zeng Qingfeng
中科院分区：
文献类型：
--
作者：
Zhang Jin;Oganov Artem R.;Li Xinfeng;Dong Huafeng;Zeng Qingfeng
为了探索新的高强度陶瓷材料，我们采用从头算方法对Zr-O体系中所有稳定的化合物进行了演化模拟。发现不仅传统的ZrO_2化合物在零压下是稳定的，而且R-ZrO_6 O、Rc-ZrO_3 O、P_1 m-ZrO_2 O和P_2 m-ZrO_3等有序低价氧化物在零压下也是稳定的。半金属P2 m-ZrO的晶体结构由Zr-石墨烯层组成，并且可以被描述为ω-Zr结构的插层版本。在P2 m-ZrO的三维能带结构中发现了一个有趣的大质量Dirac锥.系统地研究了Zr-O化合物的弹性性能、硬度以及力学性能与氧含量的关系。令人惊讶的是，最硬的氧化锆不是ZrO 2，而是ZrO。P2 m-ZrO和P1 m-ZrO分别表现出14 GPa和10 GPa的相对高的硬度值。导出了P_2 m-ZrO和P_1 m-ZrO_2 O的各向异性杨氏模量E、扭剪模量G_t和线性压缩系数β。进一步对Zr-O化合物的态密度、能带结构和晶体轨道汉密尔顿布居的分析表明，Zr-O化合物的电子结构与其力学性能有直接关系。P2 m-ZrO中Zr-O三维骨架结构和强Zr-Zr键的同时存在解释了其高硬度。
With the motivation of exploring new high-strength ceramics, ab initio evolutionary simulations are performed to search for all the stable compounds in the Zr–O system. We have found that not only the traditional compound ZrO2, but also the ordered suboxides R-Zr6O, Rc-Zr3O, P1m-Zr2O and P2m-ZrO are stable at zero pressure. The crystal structure of semimetallic P2m-ZrO consists of Zr-graphene layers and can be described as an intercalated version of the ω-Zr structure. An interesting massive Dirac cone is found in the three-dimensional (3D) band structure of P2m-ZrO at the Γ-point. The elastic properties, the hardness and the correlation between the mechanical properties of Zr–O compounds and the oxygen content have been systematically investigated. Surprisingly, the hardest zirconium oxide is not ZrO2, but ZrO. Both P2m-ZrO and P1m-Zr2O exhibit relatively high hardness values of 14 GPa and 10 GPa, respectively. The anisotropic Young's modulus E, torsion shear modulus Gt and linear compressibility β have been derived for P2m-ZrO and P1m-Zr2O. Further analyses of the density of states, the band structure and the crystal orbital Hamilton population indicate that the electronic structure of Zr–O compounds is directly related to their mechanical properties. The simultaneous occurrence of the 3D-framework of Zr–O and the strong Zr–Zr bonds in P2m-ZrO explains its high hardness.