Processing and properties of PMMN-PZT quaternary piezoelectric ceramics for ultrasonic motors

Piezoelectric Pb(Mg(1/)3Nb(1/3))O-3-Pb(Mn1/3Nb2/3)O-3-PbZrO3-PbTiO3 (PMMN-PZT) quaternary ceramics with various contents of Pb(Mn1/3Nb2/3)O-3 from 4 to 8 mol% were prepared. The conventional single-stage and columbite two-stage methods were compared. Columbites MgNb2O6 and MnNb2O6, and the phase structure of PMMN-PZT were examined using X-ray diffraction (XRD). The surface morphology was examined by SEM. Study on the effect of Pb(Mn1/3Nb2/3)O-3 additives on dielectric and piezoelectric properties indicated that the PMMN-PZT quaternary system exhibited a high mechanical quality factor and well-situated piezoelectric properties. The optimized results, of d(33) (307 pC/N), K-p (0.55) and Q(m) (2379) were obtained at 6 mol% Pb(Mn1/3Nb2/3)O-3. (C) 2002 Elsevier Science B.V. All rights reserved.