CORRELATION BETWEEN SURFACE TEXTURE AND CHEMICAL-COMPOSITION IN UNDOPED, HARD, AND SOFT PIEZOELECTRIC PZT CERAMICS

The electrical and mechanical properties of piezoelectric lead zircona te titanate (PZT) ceramics are strongly influenced by domain-wall moti on, which can be tailored via the substitution of ions within the pero vskite structure, Different domain mobilities are achieved by lead and /or oxygen vacancies, according to the valency and ionic radius of the dopants, To quantify the surface near domain mobility, hard (silver-d oped), soft (lanthanum-doped), and undoped PZT ceramics have been prep ared, An applied mechanical stress after sintering causes texturing ne ar the surface, because of the ferroelastic behavior of the 90 degrees domains, The texture is quantified via X-ray diffractometry (XRD) ana lysis of the tetragonal F-T(002)- and F-T(200)-peak intensities, using least-squares refinement with Gaussian profile functions, The samples are subsequently annealed to remove the surface texture and again cha racterized via XRD measurements, However, annealed samples still revea l a preferred domain orientation that can be removed only by a second annealing of the pulverized samples, A comparison of the tetragonal ad ditive systems clearly reveals the greatest domain mobility for lantha num-doped PZT ceramics, whereas the silver-doped and undoped samples h ave similar ferroelastic behavior, Furthermore, the surface texture of all the compositions is dependent on the applied mechanical stress an d cannot be removed completely by heat treatment.