High aspect ratio patelike NaNbO
3 particles with pure perovskite structure have been successfully synthesized by topochemical microcrystal conversion (TMC) from plate-like precursor particles of the layer-structured Bi
2.5Na
3.5Nb
5O
18. By changing the Bi
2.5Na
3.5Nb
5O
18/Na
2CO
3 ratio, large and thin NaNbO
3 particles with a thickness of approximately 0.5 μm and a width of approximately 20 μm were obtained. The obtained NaNbO
3 particles is quite suitable for fabricating textured (K
0.5Na
0.5)NbO
3-based ceramics. Using the fine platelike NaNbO
3 particles as templates, dense <001> -oriented (K
0.5Na
0.5)NbO
3-0.5 mol %MnO
2 ceramics with high texture quality (Lotgering factor
F 001 = 87 %) and excellent piezoelectric properties were produced by templated grain growth. Compared with randomly oriented ceramics, textured samples show greatly enhanced properties. The room-temperature strain
S, the piezoelectric coefficient
d 33 * and
d 33 reach up to 0.093 %, 233 pm/V and 195pC/N, respectively, which are all about 1.5 times larger than those of non-textured ceramics.
相似文献