Fabrication and characterization of Li1+x−yNb1−x−3yTix+4yO3 substrates using aqueous tape casting process

An aqueous system for tape casting Li1+x−yNb1−x−3yTix+4yO3 (LNT) ceramics was developed using poly(vinyl alcohol) (PVA) binder, ethylene alcohol (EG) plasticizer and ammonium salt of polycarboxylate (PCA-NH4) dispersant. The zeta potential measurement showed that the isoelectric point of the LNT particles moved slightly toward more acid region after the dispersant absorbed on the particles, while the zeta potential increased significantly. The rheological test indicated that the ceramic slurry exhibited a typical pseudoplastic behavior without thixotropy. The effect of solid loading on the properties of the green tapes was investigated. The increase in the solid loading increased the tensile strength and the green density of the tapes. TGA analysis indicated that the organic additives in the green tapes can be completely removed by heat treatment at 600 °C. SEM micrographs showed that the microstructure of the green and sintered tapes was homogeneous.