Hydrothermal synthesis of NaNbO₃—morphology change by starting compounds—

抄録

Perovskite-type sodium niobate, NaNbO₃ was prepared by hydrothermal reaction using an amorphous hydrated niobium oxide (a-Nb₂O₅). A single phase of perovskite-type NaNbO₃ was obtained under the condition of 160°C and 1.0 M NaOH solution, and at higher temperature (≥180°C) cubic shape particles with the size of 5–10 µm were produced. These cubic shape particles had well developed 110 and 001 planes. When other starting compounds, Nb₂O₅, HNbO₃·nH₂O and HNb₃O₈·nH₂O were used, well crystallized particles were not obtained. The particles prepared from HNbO₃·nH₂O and HNb₃O₈·nH₂O had irregular shape and cubic-like shape with the size of 1–5 µm. In the case of Nb₂O₅ fine particles with the submicron size of ∼0.5 µm were obtained.