Grain size effect on piezoelectric properties of BaTiO 3 ceramics

We demonstrated the grain size effect on piezoelectric properties of pure BaTiO 3 ceramics. BaTiO 3 ceramics with various grain sizes were prepared by conventional and two-step sintering methods. The piezoelectric strain constant d 33 increased with decreasing grain size when the grain size was more than 1.2 µm, whereas it decreased when the grain size was below 1.2 µm. The maximum d 33 was 460 pC/N, which is approximately three times larger than that of coarse BaTiO 3 ceramics. The increase in d 33 was well explained by the domain-wall contribution, while the decrease in d 33 was understood as the grain boundary effect. On the other hand, the piezoelectric voltage constant g 33 increased with decreasing grain size down to 0.6 µm. The piezoelectric constants d 33 and g 33 , and the mechanical quality factor Q m can be controlled by the grain size of BaTiO 3 ceramics.