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

Abstract

We synthesize a nanosized lanthanum silicate, La9.33Si6O26, 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 10μm.