Titanium-rich (Sr/Ti = 0.995) strontium titanate (ST) ceramics, air-sintered in a temperature range of 1400–1625 °C, were reported to possess anomalies in the grain growth and analogous anomalies in the grain boundary (GB) conductivity activation energy. However, these two interface-related phenomena, occurring at GBs, could not be associated with each other using a simple “brick-layer” model. In this work we revise the topic and advocate that the deviation from the model comes from the oxygen vacancies localized at GBs of the rapidly-cooled ST ceramics. To verify this, we annealed the ceramics in oxygen and performed their systematic and comparative analysis using impedance spectroscopy. A levelling-off in the GB conductivity activation energy, which increases for ≤1.24 eV, and a four-fold decrease in the GB permittivity are observed after annealing. Thus, we confirm a key role of oxygen vacancies in relation between the grain growth and GB conductivity anomalies of as-sintered Ti-rich ST ceramics.

据报道，在1400–1625°C的温度范围内空气烧结的富钛（Sr / Ti = 0.995）钛酸锶（ST）陶瓷在晶粒生长方面具有异常，在晶界（GB）中具有类似的异常。电导活化能。但是，使用简单的“砖层”模型无法将发生在GB上的这两种与接口相关的现象相互关联。在这项工作中，我们修改了主题，并提倡与模型的偏差来自于快速冷却的ST陶瓷的GBs处的氧空位。为了验证这一点，我们在氧气中对陶瓷进行了退火，并使用阻抗谱对它们进行了系统的比较分析。GB电导率活化能趋于平稳，在≤1.24eV时增加，退火后，观察到GB介电常数降低了四倍。因此，我们确定了氧空位在烧结后富钛ST陶瓷的晶粒长大与GB电导率异常之间的关键作用。