Preparation of Thin and Dense Lanthanum Cobaltite Coating on Porous Tubular Alumina Supports by Electrophoretic Deposition

Abstract

The electrophoretic deposition (EPD) process is one of several ceramic powder assembling technologies using a simultaneous colloidal process and electrochemical driving force. For the further development of the EPD technique, the possibility and the usefulness of preparing a thin and dense ceramic coating on non-electronically conductive porous tubular ceramics using the EPD technique was investigated. La_0.8Sr_0.2Co_0.8Sr_0.2O_3-δ (LSCF) was used as the deposition material and a porous alumina tube was used as the deposition substrate. Methanol (MeOH) was suitable as a dispersing medium for the LSCF powder. LSCF particles were positively charged in MeOH. For the fabrication of a uniform EPD layer, the cathode was placed in a porous alumina tube. The insides of the porous alumina tubes were filled with MeOH and the cathode did not make contact with the EPD bath. A 30 μm (200 g/m²) thick uniform LSCF powder coating was obtained by EPD at 100 V for 10 min. After sintering at 1500°C for 5 h, a 20 μm dense membrane was obtained.