The re-oxidation kinetics of BaTiO₃ ceramics sintered by Spark Plasma Sintering (SPS) was investigated using in-situ impedance spectroscopy. Thanks to the flexibility of the SPS process, the grain size of the dense ceramics was tuned from 0.5 μm to 10 μm. The re-oxidation kinetics are found to be very fast regardless of the grain size and a full re-oxidation of the ceramics are achieved after 20 h of exposure to an ambient environment at only 600 °C. The residual density of charge carriers is reduced when using finer starting powders. SPS ceramics made with micrometer size grains demonstrate a residual charge-carrier density that is one tenth that of ceramics made from 10 μm particles. Grain-boundary conduction is dominant through fine-grain SPS ceramics. This latter feature is similar to BaTiO₃ sintered using the conventional route with 10 μm size grain. Finally, the critical grain size for optimal dielectric permittivity is found to shift from 0.7 μm in standard ceramics to 1.5 μm in SPS ceramics.

利用原位阻抗谱研究了放电等离子体烧结（SPS）烧结的BaTiO ₃陶瓷的再氧化动力学。由于SPS工艺的灵活性，致密陶瓷的晶粒尺寸从0.5μm调整到10μm。发现无论晶粒大小如何，其再氧化动力学都非常快，并且仅在暴露于600°C的环境中20小时后，陶瓷即可实现完全再氧化。当使用更细的起始粉末时，电荷载体的残留密度降低。用微米级晶粒制成的SPS陶瓷显示出的残留电荷载流子密度是10μm颗粒制成的陶瓷的十分之一。晶粒边界传导是通过细粒SPS陶瓷占主导地位的。后一个特征类似于BaTiO ₃使用常规方法烧结的晶粒尺寸为10μm。最后，发现最佳介电常数的临界晶粒尺寸从标准陶瓷的0.7μm变为SPS陶瓷的1.5μm。