Kamini Kumari
材料科学技术（英文）
Structural and dielectric properties of polycrystalline samples of lead-free (1-x)(Na1/2Bi1/2)TiO3-xZnO, prepared using a high-temperature solid-state reaction method, are investigated in the composition range 0 ≤ x ≤ 0.10. Rietveld analyses of X-ray diffraction data indicated the formation of a single-phase hexagonal structure with R3c symmetry. Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds. Temperature dependence of dielectric constant showed that the addition of ZnO to (Na1/2Bi1/2)TiO3 shifts the phase transition temperature towards higher side, a property favourable for practical applications of these ceramics. Further, temperature dependent permittivity data provided low temperature coefficient of capacitance (TCC < 8%) up to 100°C. Furthermore, a decrease in the value of dielectric loss with an increase in ZnO content is observed.
关键词:
Lead-free
Kamini Kumari
材料科学技术（英文）
Structural and dielectric properties of polycrystalline samples of lead-free (1-x)(Na1/2Bi1/2)TiO3-xZnO, prepared using a high-temperature solid-state reaction method, are investigated in the composition range 0 ≤ x ≤ 0.10. Rietveld analyses of X-ray diffraction data indicated the formation of a single-phase hexagonal structure with R3c symmetry. Williamson-Hall approach was applied to estimate the apparent particle size and lattice strain of the compounds. Temperature dependence of dielectric constant showed that the addition of ZnO to (Na1/2Bi1/2)TiO3 shifts the phase transition temperature towards higher side, a property favourable for practical applications of these ceramics. Further, temperature dependent permittivity data provided low temperature coefficient of capacitance (TCC < 8%) up to 100°C. Furthermore, a decrease in the value of dielectric loss with an increase in ZnO content is observed.
关键词:
Lead-free
Peng QI
,
Jinfeng WANG
,
Baoquan MING
,
Juan DU
,
Xinghua LIANG
,
Limei ZHENG
材料科学技术（英文）
Lead-free piezoelectric ceramics (Na0.5K0.5-xLix)NbO3 (x=0.057–0.066) were synthesized by an ordinary sintering technique. Substituting Li for K can lead to structural distortion, which improves the Curie temperature (TC) greatly. By adding appropriate LiNbO3 content, piezoelectric constant d33 values reach 202–212 pC/N. Electromechanical coefficients of the planar mode reach 44.4%–46.8%. The dielectric loss is below 2.6%, which is much lower than reported (about 50%). The TC of (Na0.5K0.5-xLix)NbO3 (x=0.057–0.066) is in the range of 490–510oC, at least 70oC higher than that of pure (Na0.5K0.5)NbO3 ceramics. The results show that (Na0.5K0.5-xLix)NbO3 ceramic is a kind of good lead-free high-temperature piezoelectric material.
关键词:
Lead-free
,
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