Crystallization process of lanthanum-substituted bismuth titanate synthesized by a facile sol-gel method

We present a facile sol-gel route to synthesize lanthanum-substituted bismuth titanate (BLT). The chemical reactions and crystallization process of this method using the initial materials of bismuth subnitrate [4BiNO(3)(OH)(2)center dot BiO(OH)], lanthanum nitrate [La(NO(3))(3)center dot 6H(2)O] and tetrabutyl titanate [Ti(C(4)H(9)O)(4)] were investigated by thermogravimetric and differential thermal analysis, IR spectroscopy, gas chromatography/mass spectrometry, Raman spectroscopy and XRD. The evaporation of the dissolved CO(2) in the amorphous BLT matrix is associated with the crystallization of BLT. The BLT gel is pure BLT perovskite when calcination temperature is higher than 500 A degrees C. The grain size of the obtained nanoparticles ranges from 15 to 82 nm. The Arrhenius curve is obtained from the representation of the reduced sizes with respect to the calcination temperature. The activation energy of grain growth in BLT nanoparticles is 0.36 eV, which shows a rapidly growth process in the temperature range of 500-850 A degrees C.