Measurement of an electrical potential induced by normal stress applied to the interface of an ionic material at elevated temperatures
Measurement of an electrical potential induced by normal stress applied to the interface of an ionic material at elevated temperatures
复制标题
测量高温下施加到离子材料界面的正应力引起的电势
DOI：
10.1016/s1359-6454(99)00206-2
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发表时间：
1999
期刊：
影响因子：
9.4
通讯作者：
R. Raj
中科院分区：
文献类型：
--
作者：
A. Pannikkat;R. Raj
本文报道了当一个表面施加正应力，而另一个表面不施加应力时，氧化锆两个表面之间的电位差的测量。在很宽的范围内，电位差与施加的应力成正比。比例常数是一种新的界面状态的热力学测量方法，因为它是可逆的，与温度无关。在氧化锆中，通过考虑氧离子在应力和非应力界面上的电化学电位之间的热力学平衡，比例常数与氧离子的体积和电荷有关。对于（100）取向的多晶氧化锆或单晶立方氧化锆制成的样品，与理论的一致性在10%以内。对于单晶的其他取向，比例常数的变化可达20%；这种变化归因于氧离子在不同表面取向上的有效电荷的差异。对电压响应的动力学进行了详细的研究；这与氧离子沿金属电极与氧化锆表面之间形成的界面扩散是一致的。目前的测量首次在实验上证实了化学势、法向牵引力和晶体材料界面处物质的原子体积之间的基本关系。该测量对进一步理解离子（或部分离子）固体中的扩散蠕变、蠕变空化和烧结具有重要意义。
The measurement of a potential difference between two surfaces of zirconia is reported, when a normal stress is applied to one surface, leaving the other surface stress free. The potential difference is proportional to the applied stress over a wide range. The proportionality constant represents a new thermodynamic measurement of the interfacial state because the measurement is reversible and independent of temperature. In zirconia, the proportionality constant is related to the volume and the charge on the oxygen ion by considering thermodynamic equilibrium among the electrochemical potentials of the oxygen ion at the stressed and unstressed interfaces. The agreement with theory is within 10% for specimens made of polycrystalline zirconia, or single crystal cubic zirconia of (100) orientation. The proportionality constant changes by up to 20% for other orientations of the single crystal; this change is attributed to differences in the effective charge on the oxygen ion on different surface orientations. The kinetics of the voltage response was also investigated in detail; it is consistent with the diffusion of the oxygen ion along the interface formed between the metal electrode and the zirconia surface. The present measurements provide the first experimental confirmation of the fundamental relationship between the chemical potential, the normal traction, and the atomic volume of species at interfaces of crystalline materials. The measurement has implications in further understanding of diffusional creep, creep cavitation and sintering in ionic (or partially ionic) solids.