Effects of mono-substituting chelating agents on BaTiO3 prepared by the sol-gel process
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BaTiO3 of various grain size was prepared by the sol-gel process from Ti (OR)4 (R = isoC3H7 or C4H9)+Ba(CH3COO)2+chelating agent CH3COCH2COR′(R′ = CH3 or OC2H5) 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 (CH3COCHCOR′). The gelation time varied from 3 to 5 months and diminished with increasing steric hindrance. The amorphous gel was crystallized into cubic phase BaTiO3 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 BaTiO3.
KeywordsPolymer Grain Size Fourier Mass Spectrometry Fourier Transform
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