Advantages of low partial pressure of oxygen processing of alkali niobate: NaNbO₃

This work focused on the processing of low oxygen partial pressure (low-pO₂) calcination and sintering with respect to NaNbO₃ (NN) of one key member in ferroelectric (Na,K)NbO₃. The high-density NN ceramics were successfully prepared without any sintering additives using the low-pO₂ process. Comparing conventional air process, the low-pO₂ calcined NN powders showed lower defect concentration and higher densification. The low-pO₂ sintered NN ceramics had dielectric constant and dielectric loss performance at high temperatures. Furthermore, the low-pO₂ sintered NN ceramics indicated ferroelectric behavior, and both maximum polarization and strain improved to two to three times that of conventional air-sintered NN ceramics. From this relatively simple compound, NN, the advantage of low-pO₂ is unambiguously demonstrated and points to its consideration. It is hypotheses as a kinetically controlled process that limits the volatility under low-pO₂ condition.