Effect of compaction pressure on sinterability, microstructure and electrical behavior of Ba0.5Na0.48Sr0.02TiO3 system

Abstract

The microstructure of electroceramics is a highly influencing factor to decide its functionality and applicability. Processing conditions used for the conversion of raw powder of electroceramics to the net product are playing a dominant role to modulate microstructure. In the present attempt, various compaction pressures (5 tons/cm2, 7 tons/cm2, and 9 tons/cm2) are used to densify the powder sample to the pellet. The effect of the pressure on sinterability, microstructure, and electrical behavior is systematically revealed. Ba0.5Na0.48Sr0.02TiO3 (BNST) with optimized composition has been prepared by the sol-gel combustion method. The structure is confirmed by X-ray diffraction and accompanied by Rietveld refinements. The compaction pressure effect on sinterability is systematically studied by revealing variation of relative density as a function of temperature at constant holding time as well as a function of holding time at a constant temperature. The final obtained relative density is found to be strongly affected by compaction pressure. Microstructural changes during the sintering process are closely monitored and found porosity, grain size, and grain size distribution are strongly affected by compaction pressure. That indirectly influenced electrical behavior. Relaxation frequency and activation energy of charge relaxation are also found to be varied with the compaction pressure of the powder samples.