Preparation of Plate‐Like Sodium Niobate Particles by Hydrothermal Method

Sodium niobate NaNbO 3 hydrate ( NN ‐hydrate) particles with a plate‐like morphology were prepared at 140°C for 2 h in 12 mol/L of NaOH by the hydrothermal method. Bar‐like Na 8 Nb 6 O 19 ·13H 2 O particles were synthesized at as low as 100°C for 2 h. This work demonstrates that by carefully optimizing the reaction condition, we can selectively fabricate niobate structures, including the bar‐like, plate‐like, fibers and cube particles through a direct reaction between NaOH solution and Nb 2 O 5 . It was found that Nb 6 O 19 8− formed was an important premise for formation of the NN ‐hydrate, and lower [ OH – ] was not favorable in preparing the NN ‐hydrate as there was an optimum [ OH − ]. Through researching effects of the reaction temperature, time, concentration of NaOH , and content of Nb 2 O 5 on the NN ‐hydrate structure and evolution, the formation mechanism from solid reactants to the intermediate were investigated. After calcining at 800°C, the synthesized NN ‐hydrate particles made a phase almost transform to the perovskite NaNbO 3 , and the morphology of these calcined particles was still plate‐like.