Synthesis of Plate-Like (Ce,Sr)PO₄ and Preparation of Oriented Film by Electrophoretic Deposition Method

Abstract

In recent years, a hydrogen permeation film using a proton-electron mixed conductor has drawn much attention as a hydrogen-production process. In this work, we focus on (Ce,Sr)PO₄ with the monazite-type structure as the mixed conducting ceramics, and aim to synthesize the plate-like powder by means of the hydrothermal method. As a result, it is found that micaceous powders with the single phase can be obtained successfully. From crystal-structure analyses using synchrotron X-ray diffractions, it is suggested that Sr replaces Ce in the crystal and thus (Ce,Sr)PO₄ can be synthesized. This result is also supported by the electrical-conductivity measurements. In order to tailor an oriented film of the orthophosphate, we perform the electrophoretic deposition using the plate-like powders. As a result, it is demonstrated that the deposited film can be obtained by adding I₂ into an acetone deposition bath and the deposition amount can be controlled by the deposition voltage and time. It is also found that the prepared film tends to be oriented by applying lower deposition voltage.