Effect of fluxing additive on sintering temperature, microstructure and properties of BaTiO3

Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0 center dot 3 wt% Li2CO3 addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO3 was investigated in the present study. The addition of 0 center dot 3 wt% Li2CO3 was observed to lower the optimum sintering temperature by similar to 200A degrees C with no second phase formation and cause a five-fold reduction in grain size. Rhombohedral-to-orthorhombic and tetragonal-to-cubic phase transitions at the expected temperatures were evident from the Raman spectra, but the orthorhombic-to-tetragonal phase transition was not clearly discernible. The persistence of various phase(s) at higher temperatures in the flux-added materials indicated that the phase transitions occurred relatively slowly. A decrease in dielectric constant of Li2O-added BaTiO3 in comparison to pure BaTiO3 may be due to the diminished dielectric polarizability of Li (+) in comparison to Ba2 + .