Preparation of Ion-Exchangeable Thin Films of Layered Niobate K₄Nb₆O₁₇

An ion-exchangeable thin film which has the layered structure of K 4 Nb 6 O 17 was prepared from a suspension of fine particles of K 4 Nb 6 O 17 . The superfine particles which were obtained by wet grinding were coated onto a substrate, and they were calcined between 873 and 1073 K. Crystallization of the fine particles by calcination was observed by XRD, SEM, and AFM, and very flat crystals of ∼500 nm with the b -axis perpendicular to the substrate surface were obtained by calcination at 1027 K. The obtained thin film had a layered structure similar to that of the original K 4 Nb 6 O 17 powder. Furthermore, it had ion-exchange properties which enabled the exchange of interlayer cations from potassium to others without destroying the layered structure.