Diol-based sol-gel as a novel binder for barium titanate ceramics

The relative merits of using a diol-based sol-gel precursor as a binder in the fabrication of barium titanate ceramics made by die- pressing a mixed oxide starting powder have been investigated. The characteristics of powder compacts were compared to samples prepared using a conventional PVB organic binder. The green strength of pellets with the PVB binder was higher than for samples containing the gel, but strength after binder burnout from gel samples was double that of pellets made with PVB. The gel led to improvements in densification during sintering, but these were most noticeable at low sintering temperatures and at intermediate stages of densification. After sintering for 2 h at 1150 degrees C, the gel-containing samples reached 75% of theoretical density, some 5% more than for the organic polymer binder. Sintering at 1300 degrees C for 2 h, gave a sintered density of similar to 96% of theoretical density using the gel additive, which was only 2% higher than for the conventional PVB binder system. The decomposition characteristics of the gel were investigated by TGA, FTIR and GC- MS techniques.