Zhang Ping, Zhao Yonggui, Wang Xiuyu
School of Electronic and Information Engineering, Tianjin University, Tianjin 300072, China.
Dalton Trans. 2015 Jun 28;44(24):10932-8. doi: 10.1039/c5dt01343g. Epub 2015 May 22.
The crystalline structure refinement, chemical bond ionicity, lattice energy and coefficient of thermal expansion were carried out for Nd(Nb(1-x)Sb(x))O4 ceramics with a monoclinic fergusonite structure to investigate the correlations between the crystalline structure, phase stability, bond ionicity, lattice energy, coefficient of thermal expansion, and microwave dielectric properties. The bond ionicity, lattice energy, and coefficient of thermal expansion of Nd(Nb(1-x)Sb(x))O4 ceramics were calculated using a semiempirical method based on the complex bond theory. The phase structure stability varied with the lattice energy which was resulted by the substitution constant of Sb(5+). With the increasing of the Sb(5+) contents, the decrease of Nb/Sb-O bond ionicity was observed, which could be contributed to the electric polarization. The ε(r) had a close relationship with the Nb/Sb-O bond ionicity. The increase of the Q×f and |τ(f)| values could be attributed to the lattice energy and the coefficient of thermal expansion. The microwave dielectric properties of Nd(Nb(1-x)Sb(x))O4 ceramics with the monoclinic fergusonite structure were strongly dependent on the chemical bond ionicity, lattice energy and coefficient of thermal expansion.
对具有单斜磷钇矿结构的Nd(Nb(1-x)Sb(x))O4陶瓷进行了晶体结构细化、化学键离子性、晶格能和热膨胀系数的研究，以探讨晶体结构、相稳定性、键离子性、晶格能、热膨胀系数与微波介电性能之间的相关性。采用基于复键理论的半经验方法计算了Nd(Nb(1-x)Sb(x))O4陶瓷的键离子性、晶格能和热膨胀系数。相结构稳定性随由Sb(5+)取代常数引起的晶格能而变化。随着Sb(5+)含量的增加，观察到Nb/Sb-O键离子性降低，这可能归因于极化。ε(r)与Nb/Sb-O键离子性密切相关。Q×f和|τ(f)|值的增加可归因于晶格能和热膨胀系数。具有单斜磷钇矿结构的Nd(Nb(1-x)Sb(x))O4陶瓷的微波介电性能强烈依赖于化学键离子性、晶格能和热膨胀系数。
