A novel standing wave linear ultrasonic motor operating in in-plane expanding and bending modes was proposed in this study. The stator (or actuator) of the linear motor was made of a simple single Lead Zirconate Titanate (PZT) ceramic square plate (15 × 15 × 2 mm³) with a circular hole (D = 6.7 mm) in the center. The geometric parameters of the stator were computed with the finite element analysis to produce in-plane bi-mode standing wave vibration. The calculated results predicted that a driving tip attached at midpoint of one edge of the stator can produce two orthogonal, approximate straight-line trajectories, which can be used to move a slider in linear motion via frictional forces in forward or reverse direction. The investigations showed that the proposed linear motor can produce a six times higher power density than that of a previously reported square plate motor.

Electric-field-induced strains of BiScO ₃ -PbTiO ₃ (BS-PT) ceramics and actuation performance in multilayer configuration were investigated in the temperature range from 25°C to 250°C. Experimental results confirmed that BS-PT ceramics showed better piezoelectric temperature stability than PZT-5H ceramics, and larger strain than PZT-4 and PZT-8 ceramics at temperatures above 50°C. The strain of a BSPT multilayer actuator prepared by the silicate-cement-glue method was comparable to that of a single-layer BS-PT ceramic. Under ±7.5 kV/cm electric field, the strain of a BS-PT multilayer actuator reached 0.115% at 200°C. Our work shows that BS-PT ceramics are suitable for high-temperature actuation applications.

We report a hollow type piezoelectric micromotor made of a PZT ceramic/metal composite cylinder with sizes of only 3.6 mm in diameter and 3.0 mm in length aiming at medical endoscope application. The hollow piezoelectric stator of the micromotor, acting as a nut, can excite E₀₂-mode traveling wave along its circumferential direction, and a hollow rotor with a fine lens inside, acting as a screw, is driven to produce a spiral motion along its axis direction inside the hollow stator via the traveling wave. The features of the developed micromotors are its hollow, fine structure and submicrometer step resolution, ensuring that the optical path passes in a narrow and limited space and that the optical focal length is tuned precisely inside the endoscope, which is meaningful in medical diagnosis.

Cobalt-modified 0.40Bi(Sc_3/4In_1/4)O₃–0.58PbTiO₃–0.02Pb(Mg_1/3Nb_2/3)O₃ ceramics (abbreviated as BSI–PT–PMN–xCo) were produced by conventional two-step solid-state processing. The phase structure, micro structure morphology, and electrical properties of BSI–PT–PMN–xCo were systematically studied. The introduction of Co ions exerted a significant influence on the structure and electrical properties. The experiment results demonstrated that Co ions entered the B-sites of the lattice, resulting in slight lattice distortion and a smaller lattice constant. The average grain size increased from ~1.94 μm to ~2.68 μm with the increasing Co content. The optimized comprehensive electrical properties were obtained with proper Co-modified content 0.2 wt.%. The Curie temperature (T_c) was 412 °C, the piezoelectric constant (d₃₃) was 370 pC/N, the remnant polarization (P_r) was 29.2 μC/cm², the relatively dielectric constant (ε_r) was 1450, the planar electromechanical coupling coefficient (k_p) was 46.5, and the dielectric loss (tanδ) was 0.051. Together with the enhanced DC resistivity of 10⁹ Ω cm under 300 °C and good thermal stability, BSI–PT–PMN–0.2Co ceramic is a promising candidate material for high-temperature piezoelectric applications.