Effect of Fluxing Additive on Sintering Temperature, Microstructure and Properties of BaTiO₃

Yaseen Iqbal, University of Peshawar
Asad Jamal, University of Peshawar
Riaz Ullah, University of Peshawar
M. Naeem Khan, University of Peshawar
Rick Ubic, Boise State University

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This document was originally published by Indian Academy of Sciences in Bulletin of Materials Science. Copyright restrictions may apply. www.ias.ac.in/matersci/

Abstract

Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0·3wt% Li₂CO₃ addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO₃ was investigated in the present study. The addition of 0·3wt% Li2CO₃ was observed to lower the optimum sintering temperature by ∼200^◦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-totetragonal 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⁺.