Processing and characterization of high Q(m) ferroelectric ceramics

Use of ferroelectric ceramics in applications like piezoelectric transforme rs was made possible by the development of new materials with high electrom echanical coupling coefficients and high mechanical quality factor. 'Hard" ferroelectric ceramics of complex composition based on lead zirconate titan ate with Nb, Mg, Mn and Li additives have been prepared. The perovskitic ph ase was produced by solid phase reaction of the oxides. The crucial role pl ayed by the intermediate mixing and grinding procedures in the assessment o f the final properties of the material was investigated. Densification up t o approximately the theoretical density value was achieved. The polarizatio n was obtained by subjecting the samples at 30 kV cm(-1) poling electric fi eld, in a silicon oil bath heated at 120 degrees C. Their structural and mo rphological properties were checked by X-ray diffraction analysis and scann ing electron microscopy. Ferroelectric and piezoelectric properties were de termined in agreement with IEEE measurement standards. The optimized sample s presented very high quality and electromechanical coupling factors, toget her with small dielectric loss. (C) 1999 Elsevier Science Limited. All righ ts reserved.