Usa Sukkha

Effect of Pb(Y1/2Nb1/2)O3 Additions on Thermal and Electrical Properties of PbZrO3 Ceramics

The solid solution of a (1–x)PbZrO3 – xPb(Y1/2Nb1/2)O3 (PZ – PYN) system, with x = 0.00 – 0.08, was synthesized by the wolframite precursor method. The effects of PYN content on crystal structure, and electrical and thermal properties of PbZrO3 ceramic were investigated. The crystal structure of sintered ceramics was characterized by X-ray diffraction. The pure perovskite phase was obtained for all compositions. The transition temperatures of the AFE to PE phase become lower with PYN increase. The dielectric properties of PZ were improved by the addition of PYN.

Dielectric, Ferroelectric and Piezoelectric Properties of the Lead Free 0.9BaTiO3-(0.1-x)Bi0.5Na0.5TiO3-xBi(Mg0.5Ti0.5)O3 Solid Solution

Solid solution of 0.9BaTiO3-(0.1-x)Bi0.5Na0.5TiO3-xBi(Mg0.5Ti0.5)O3 (BT-BNT-xBMT) system, where x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, was synthesized by the solid state reaction. Dense BT-BNT-xBMT ceramics were obtained by sintering at 1,150–1,250˚C for 4 h. The effect of BMT on crystal structure and electrical property of BT-BNT ceramics was investigated as a function of composition, x, using X-ray diffraction, dielectric spectroscopy, hysteresis and strain measurements. The crystal structure of solid solution BT-BNT-xBMT, where x = 0.00-0.10, successively transforms from tetragonal to pseudocubic symmetry, with increased BMT concentration. Temperature dependence of dielectric constant (ϵr) and dielectric loss (tanδ) for BT-BNT-xBMT at various frequencies showed that phase transition of ceramics changed from ferroelectric to relaxor-like behavior as BMT content increased. Furthermore, remanent polarization (Pr), coercive field (Ec) and the normalized strain (d33*) of BT-BNT-xBMT ceramics tend to decrease with increasing BMT concentration.

Effect of Pb(Ni1/2W1/2)O3 on the Phase Transition Behavior of PbZrO3 Ceramic

Solid solution of (1−x)PbZrO3−xPb(Ni1/2W1/2)O3;(1−x)PZ-xPNW ceramics, where x = 0.02-0.10, were prepared by solid state reaction. Dense (1−x)PZ – xPNW ceramics were obtained by sintering at 1,100°C for 4 h. Effect of PNW on crystal structure, phase transitions and thermal and electrical properties was investigated using X-ray diffraction, dielectric spectroscopy, hysteresis measurement and differential scanning calorimetry. The results indicated that the solubility limit of the (1−x)PZ–xPNW system was found at x = 0.04. It was proved that the intermediate phase is an antiferroelectric in the PZ-PNW system. Stability of the AFE intermediate phase was seen to improve with increasing PNW content.

Effect of BiYbO3 Addition with a Small Tolerance Factor on Ferroelectricity and TC in PbZrO3 Ceramics

Perovskite (Pb(1–3x/2)Bix)(Zr(1–3x/4)Ybx)O3 (PZ-BY) ceramics, where x = 0.01–0.10, were synthesized by conventional solid state reaction. The effect of BiYbO3 on crystal structure, phase transitions and electrical properties was studied as a function of composition. The X-ray diffraction (XRD) result indicated that the perovskite structure with orthorhombic symmetry was a major phase for all samples. The pyrochlore phase, identified as Yb0.2Zr0.8O1.9, coexists in PZ-BY ceramics. The influence of instability and a small tolerance factor (t) and the average electronegativity difference () of pure BY on phase formation of PZ-BY ceramic has been discussed. Furthermore, it was found that adding small tolerance factor BiYbO3 compound can stabilize the antiferroelectric (AFE) phase of PZ solid solutions and decreasing t of solid solution can enhance Curie temperature of PZ.