Effect of Sintering Temperatures on the Piezoelectric and Dielectric Properties of 0.98(Na0.5K0.5)NbO3-0.02(Ba0.5Ca0.5)TiO3 Ceramics

Abstract

Lead-free 0.98(Na0.5K0.5)NbO3-0.02(Ba0.5Ca0.5)TiO3 (0.98NKN-0.02BCT) ceramics were produced by using a conventional mixed oxide method with sintering temperature from 1080 degrees C to 1120 degrees C and their piezoelectric properties were investigated. The results indicate that the sintering temperature influences the electrical and the piezoelectric properties of 0.98NKN-0.02BCT ceramics. For the 0.98NKN-0.02BCT ceramics sintered from 1080 degrees C to 1120 degrees C, the piezoelectric constant d(33), electromechanical coupling factor k(p), remnant polarization values P-r and curie temperature T-c increased with increase sintering temperature. However, for 0.98NKN-0.02BCT sintered above 1100 degrees C, their values decreased. Piezoelectric properties of d(33) = 210 rho C/N and k(p) = 46%, ferroelectric properties of P-r = 16,2 mu C/cm(2) and dielectric constant epsilon(r) = 5159 were obtained for specimen sintered at 1100 degrees C for 4 h. Therefore, the 0.98NKN-0.02BCT ceramics are excellent candidate materials for lead-free piezoelectric ceramics.