Sintering Mechanism and Enhanced Piezoelectric and Crystal Structural Properties of (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 Lead Free Ceramics

A lead-free piezoelectric ceramic, (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (hereafter (1-x)BZT-xBCT), was investigated for functional device applications. Lead-free piezoelectric materials with high piezoelectric charge coefficients and voltage coefficients are indispensable for functional industrial applications. Piezoelectric ceramic specimens tend to shrink in size during the sintering process without melting. This study focused on this phenomenon as a unique characteristic of piezoelectric ceramic materials, and derived the materials' activation energies from this phenomenon, employing the Arrhenius relationship. Then the estimated activation energy was employed to determine the relationship between the piezoelectric properties and crystalline properties, while varying sintering temperature and chemical stoichiometric composition. Piezoelectric properties can change depending on the sintering temperature and process conditions. Crystalline properties and piezoelectric properties can be influenced by the sintering temperature and holding times. In this research, sintering temperature dependent structural and dielectric properties were investigated. (1-x)BZT-xBCT ceramics showed the highest piezoelectric coefficient of 470 pC/N. Sintering temperature dependent shrinkage rate and activation energy were estimated and calculated for the various sintering processes. In this research, two different activation energies for the shrinkage process were estimated.