Abstract
Nano-porous NaNbO3 was successfully synthesized from Na-Nb ethoxide by sol-crystal method. Structural characterization of specimens annealed at various temperatures was performed by a transmission electron microscope (TEM) and X-ray diffractometory. The single crystal of Na-Nb ethoxid was decomposed to an amorphous matrix below 473K. Small crystals were grown by heating above 573K, and the crystal sizes became larger with increasing temperature. At 673K, well crystallized NaNbO3 grain with an orthorhombic structure (S.G. Pbcm) was observed. The three-dimensional image constructed by a tomography system showed that the grain had many inner-pores with a few ten nano-meter sizes. Thermal behavior of the inner-pore could be observed in-situ with a TEM using a heating stage during the crystallization process.
