Lead-free BCT-xBZT solid solutions were prepared by the conventional solid-state reaction route. A full set of elastic, piezoelectric, and dielectric parameters were measured using a resonance method and calculated following the formulae in the IEEE standard for piezoelectric ceramics. In addition, ferroelectric properties were also investigated to demonstrate the "softening" and the diffuse transitions in the material.

This article studies the microstructure and piezoelectric properties of low sintering temperature lead-free ceramics [Formula: see text]-doped with ZnO nanoparticles (noted as 0.48BZT-y, y is content of ZnO in wt%, y =0.00, 0.05, 0.10, 0.15, 0.20 and 0.25). The obtained results of Raman scattering and dielectric measurements have confirmed that [Formula: see text] has occupied B site, to cause a deformation in the ABO3-type lattice of the 0.48BZT-y compounds. The 0.15 wt% ZnO-doped ceramic sintered at 1350[Formula: see text]C exhibited excellent piezoelectric parameters: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. The obtained results indicate that the high-quality lead-free BZT–BCT ceramic could be successfully synthesized at a low sintering temperature of 1350[Formula: see text]C by doping an appropriated amount of ZnO.

In this work, the vibration characteristics of a piezoelectric ceramic disk with different dimensional ratio are studied by simulation method. Computational finite element modeling combined with the computational programs has allowed for the prediction of the effect, the change of diameter-to-thickness ratio on the resonant characteristics, the vibration modes as well as comparing the physic properties of piezoceramics. Three types of piezoelectric materials were chosen, piezoelectric materials (PZT) and Pb-free piezoelectric materials Ba(Zr 0.2 Ti 0.8)O 3-50(Ba 0.7 Ca 0.3)TiO 3 (BZT-50BCT), BaTiO 3 for research.

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This paper presents a study on optimum determination of partial ratios of mechanical drive systems using a chain drive and two-step helical gearbox for getting minimum size of the system. The chosen objective function was the cross section dimension of the system. In solving the optimization problem, the design equation for pitting resistance of a gear set was investigated and equations on moment equilibrium condition of a mechanic system including a chain drive and two helical gear units and their regular resistance condition were analyses. From the results of the study, effective formulas for determination of the partial ratios of the chain drive and two-step helical gearboxes were introduced. As the formulas are explicit, the partial ratios can be calculated accurately and simply.