Hydrothermal synthesis of lanthanum silicate nanopowder and film preparation by electrophoretic deposition method

抄録

We synthesize a nanosized lanthanum silicate, La_9.33Si₆O₂₆, by means of a hydrothermal method, and then investigate the crystal structure by the Rietveld analysis and the maximum-entropy method using a neutron Bragg profile. In addition, we study electrical conduction properties of the sintered pellet with conductivity measurements under O₂ oxidizing and Ar reducing conditions. From these results, it is indicated that the oxyapatite-type lanthanum silicate with oxide-ion conduction can be prepared at 180°C hydrothermally. By using the nanopowder, we prepare a film of the lanthanum silicate via the electrophoretic deposition. As a result, it is demonstrated that a deposited film can be made successfully in an I₂-added acetone bath and the thickness obtained in an optimized condition is around 10 µm.