A series of phase transitions in (1-x)NaNbO₃-xBaZrO₃ ((1-x)NN-xBZ) ceramics was observed from antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase and finally into ferroelectric rhombohedral phase with increasing x. An electric field induced irreversible phase transition was found in different compositions, irrespective of their virgin phase structures. Particularly, an antiferroelectric orthorhombic phase is irreversibly transformed into a ferroelectric monoclinic phase within 0.02 ≤ x ≤ 0.05, leading to a giant poling strain of ∼0.58%. This is much larger than that observed in ferroelectric orthorhombic (0.06 ≤ x ≤ 0.07) and rhombohedral phases (0.08 ≤ x ≤ 0.11) suffering from an irreversible ferroelectric-ferroelectric (monoclinic) phase transition. The synchrotron x-ray diffraction and the measurement of longitudinal and transverse strains suggest that this irreversible phase transition should involve not only a distinct volume expansion, but also an obvious lattice elongation. The present study demonstrates a unique nature of the composition and field dependent phase stability and an underlying mechanism of giant poling strains in NN-BZ ceramics.

（1-x）NaNbO ₃ -xBaZrO _3中的一系列相变观察到（（1-x）NN-xBZ）陶瓷从反铁电斜方相到铁电斜方相，最终随着x的增加而变成铁电菱面体相。电场诱导的不可逆相变存在于不同的成分中，而不管其原始相结构如何。特别是，反铁电斜方晶相不可逆地转变为0.02≤x≤0.05范围内的铁电单斜晶相，导致极化极化率为〜0.58％。这比在铁电正交（0.06≤x≤0.07）和菱形相（0.08≤x≤0.11）遭受不可逆的铁电-铁电（单斜）相变时观察到的要大得多。同步加速器X射线衍射以及纵向和横向应变的测量表明，这种不可逆的相变不仅应包括明显的体积膨胀，而且还应包括明显的晶格伸长。本研究证明了NN-BZ陶瓷中成分和场相稳定性的独特性质以及巨大极化应变的潜在机理。