ISSN: 2249–9504
CAS CODEN: IJPCDX

PHASE STRUCTURE, DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF MODIFIED-PZT CERAMICS NEAR THE MORPHOTROPIC PHASE BOUNDARY

Abstract

Author(s): Necira Zelikha, Boutarfaia Ahmed1,Kharief Amel,Menasra Hayet, Bounab Karima, Abba Malika, Abdessalem Nora and Meklid Abdelhek

Modified-PZT ceramics with a formulaPb[(ZrxTi(0.98 x)(Mg1/3Nb2/3)0.01(Ni1/3Sb2/3)0.01] O3(doped with hardeners: Mg2+; Ni2+and softeners: Nb5+; Sb5+ions)abbreviated as PZT-PMN-PNS quaternary system with varying Zr/Ti ratios in the range: 0.42 ≤ x ≤ 0.54 located near the morphotropic phase boundary (MPB) were prepared by conventional solid state process.The phase structure, dielectric and piezoelectric properties of the system were investigated. Phase analysis using X-ray diffraction (XRD) indicated that the phase structure of sintered PZT-PMN-PNS ceramics was transformed from tetragonal to rhombohedral, with Zr/Ti ratio increased in system. The MPB, in which the tetragonal and rhombohedral phases coexist, is in a composition range of Zr content from 48 to 52 mol%.Scanning electron micrographs of sintered ceramic surfaces (at 1180°C)showed the dense and uniform microstructure for composition close to MPB (Zr/Ti = 50/48)with apparent density of 7.9 g/cm3(≈ 98 % of the theoretic density). For 1.0 mol% (Mg, Nb) and 1.0 mol% (Ni, Sb) doped PZT compositionwith x = 50,electrical properties were significantly improved. The main parameters of Pb [Zr0.50 Ti 0.48(Mg1/3 Nb2/3)0.01(Ni1/3 Sb2/3)0.01]O3piezoceramic system are: εr(max)= 16624.79at 1 kHz, Tc = 340 ?C,tgδ= 0.86 %, ρ= 22.85 (*106?.cm), -d31= 120.4 pC/N, Kp = 0.69, Qm= 461.9. The properties of this type of ceramics make it a very promising piezoelectric material for device applications.

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