Ferroelectric phase has been discovered in dense sodium niobate NaNbO₃ ceramic sintered by two-step method. At ambient temperature, its absolute principal rhombohedral phase R3c rather than antiferroelectric phase Pbcm was detected by X-ray diffraction measurements. And its grains with small size were observed by scanning electron microscope. Its changes of dielectric properties, enhanced ferroelectricity, and weakened piezoelectricity are related and may be ascribed to the dominant ferroelectric phase R3c of small size grains, compared with those of NaNbO₃ ceramic sintered by solid-state reaction procedure. The results demonstrate a relationship of phase transitions, domain rotation, and piezoelectric coupling mechanism: indicating the means to achieve stable ferroelectric state of NaNbO₃ with small grain size by employing the two-step method, and its potential energy-storage application.

在两步法烧结的致密铌酸钠NaNbO ₃陶瓷中发现了铁电相。在环境温度下，通过X射线衍射测量可检测到其绝对主菱形相R3c而不是反铁电相Pbcm。并用扫描电镜观察了其晶粒细小。与NaNbO ₃相比，它的介电特性，增强的铁电性和减弱的压电性的变化是相关的，并且可能归因于小尺寸晶粒的主要铁电相R3c。固态反应程序烧结的陶瓷。结果证明了相变，畴旋转和压电耦合机制之间的关系：表明了采用两步法实现具有小晶粒尺寸的NaNbO _3的稳定铁电态的方法及其潜在的储能应用。