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摘要
A series of ferroelectric ceramics with variable compositions of (1-x)PZT-x(0.2PFN-0.2PZN-0.6PNN) (x=0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by the precursor method. The proveskite structure and ferroelectric domains were studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The morphotropic phase boundary was determined and the relations among electric property, composition and microstructure were briefly discussed. It was found from XRD data that with an increase of x value the crystal structures transformed from tetragonal to rhombohedral phase. The transformations from herringbone-like domain patterns with parallel stripes to small relaxor ferroelectric domains, observed by TEM, significantly influenced the electric properties. The Curie temperature decreased apparently with the increase of x values according to the temperature-dependent relative permittivity measurements. The typical feature of relaxor ferroelectrics was observed at x≥0.3 with the maximum dielectric constants of 3050 at x=0.3. At x=0.2 the ceramics exhibited excellent dielectric, piezoelectric and ferroelectric properties: the maximal piezoelectric coefficient reached 485pC/N with the maximal remnant polarization being 37 μC/cm2. The maximal relative dielectric constant of 22000 was achieved at Curie temperature. The morphotropic phase boundary was determined to be 0.2<x<0.3 based on the experiment.
- 出版日期2011
- 单位厦门大学
