Pairing high piezoelectric properties and enhanced thermal stability in grain-oriented BNT-based lead-free piezoceramics

(Bi_0.5Na_0.5)TiO₃ (BNT)-based piezoceramics usually exhibit enhanced piezoelectric coefficient d₃₃ together with the deterioration of depolarization temperature T_d, which is the common drawback limiting their use in practical application. Here, we demonstrate that harnessing the microstructure in BNT-based ceramics will be an efficient way to resolve this obstacle. <00l> oriented piezoelectric ceramics 0.94(Bi_0.5Na_0.5)TiO₃ ?0.06BaTiO₃ was engineered by templated grain growth (TGG) using NaNbO₃ (NN) as templates. The manufactured textured ceramics with the optimized microstructure was characterized by not only approximately 200% enhancement in the magnitude of piezoelectric response (d₃₃~297pC/N) but also improved thermal stability (T_d~57?°C) in comparison to its randomly oriented counterparts (d₃₃~151pC/N and T_d~32?°C). Moreover, the enhanced piezoelectricity in grain oriented specimens primarily originated from a high degree of non-180° domain switching as compared to the randomly axed ones. The current study opens the door to pair high piezoelectric properties and enhanced thermal stability in BNT-related materials though texture technique.