PREPARATION AND PROPERTIES OF NIOBIUM-DOPED PB[(SC1 2NB1/2)(0.58)TI-0.42]O-3 CERAMICS USING HOT ISOSTATIC PRESSING/

1 mol% Nb-doped Pb[(Sc1/2Nb1/2)(0.58)Ti-0.42]O-3 (PSNTN) ceramics with the morphotropic phase boundary (hi PB) composition were prepared by the hot isostatic pressing (HIP) method to improve their physical and ferroelectric properties. Sintering, hot isostatic pressing, and annea ling conditions were optimized to produce high-density PSNTN ceramics and utilize their excellent dielectric and piezoelectric properties. U sing hot isostatic pressing after conventional sintering at 1275 degre es C for 2 h, the achieved density of PSNTN hot-isostatically pressed at 1000 degrees C was 8.00 g/cm(3), which was approximately 99.5% of t he theoretical value. The maximum dielectric constant of epsilon(33)(T )/epsilon(0) was 2900 at room temperature, and its dissipation factor was 1.5%. Large electromechanical coupling factors of k(p)=70% and k(t )=55% were obtained. The remanent polarization P-r and coercive field E(c) were 27 mu C/cm(2) and 6.9 kV/cm, respectively. The PSNTN ceramic is a promising material for applications to electromechanical bulk tr ansducers, because of its large coupling, high dielectric constant and low mechanical quality factor.