Sol-gel synthesis and characterization of barium titanate powders

A simple aqueous sol-gel route has been refined to prepare yttrium-doped ba rium titanate powders. Thermal decomposition of the fabricated gel was stud ied by means of DTA/TGA measurements. The precursor gel was intermediate ca lcined at 600 degrees C, and the final synthesis products were characterize d by IR spectroscopy, X-ray powder diffraction and scanning electron micros copy. The barium titanate obtained from the calcination of the gel at 1300 degrees C was a tetragonal phase, and showed a positive temperature coeffic ient of resistivity (PTCR) effect which depends on sample cooling rate duri ng the final heat treatment. (C) 1999 Kluwer Academic Publishers.