Stability of Suspensions and Manufacturing of Electrolyte Films

摘要

Ceramic electrolyte films are prepared by deposition of the slurries (or suspensions). The nature and composition of its constituents play a critical role in the suspension stability and film′s performance. It is therefore important to stabilise the precursor suspension of the electrolyte films. The more stable slurry will have a higher zeta potential and leads to a smaller viscosity. In this work the best conditions for the preparation of suspensions for the films for SOFC electrolyte were studied. For this intent the influence of the concentration of binder, PVA poly(vinyl alcohol), and dispersant, MFO (Menhaden Fish Oil), on the stability of the YSZ suspension precursors of electrolyte films for solid oxide fuel cells (SOFCs) was studied by zeta potential and rheological measurements. According to these results it was observed that the best concentration was of 1.0 % wt/wt for both binder and dispersant. The films were made-up according to the optimized conditions for the fabrication of the suspensions. The films were deposited by spray coating on the NiO/YSZ anode. This technique was appropriated to obtain a dense and homogeneous film. The films which were sintered at 1500o C for 6 hours showed 1.0 % of porosity, according to the treatment of the scanning electron microscopy images.