Abstract
BaTiO 3 of various grain size was prepared by the sol-gel process from Ti (OR) 4 (R = isoC 3 H 7 or C 4 H 9 )+Ba(CH 3 COO) 2 +chelating agent CH 3 COCH 2 COR′(R′ = CH 3 or OC 2 H 5 ) in a composition of equal molar ratio. Fourier transform infrared and fast atom bombardment mass spectrometry analyses suggested that the chelating agent substituted for one of the OR groups in Ti (OR) 4 to form Ti (OR) 3 (CH 3 COCHCOR′). The gelation time varied from 3 to 5 months and diminished with increasing steric hindrance. The amorphous gel was crystallized into cubic phase BaTiO 3 upon heating above 650°C. The tetragonal phase was obtained after heating for 1 h at 1350°C with the theoretical Ba/Ti ratio and 1.0096 c/a value. The measured dielectric constants diminished with increasing grain size. The results illustrated the merits of altering the chemistry of the precursors to control the properties of the BaTiO 3 . © 1994 Chapman & Hall.