Multilayer Piezoelectric Ceramic Actuator Research Articles

High-performance (K,Na)NbO 3-based multilayer piezoelectric ceramic actuators with nickel inner electrodes

High-performance (K,Na)NbO ₃-based multilayer piezoelectric ceramic actuators with nickel inner electrodes

A low-cost multilayer piezoelectric actuator for ultrasonic motor stator driving fabricated by a low-temperature co-fired ceramic process

Multilayer piezoelectric ceramics have wide application prospects in the fields of precision driving and intelligent sensing owing to their low driving voltages and large strains. However, high sintering temperatures and expensive noble metal electrodes limit their application as multilayer piezoelectric ceramic actuators (MLAs) in conventional devices. In this study, a modified piezoelectric ceramic powder and Ag inner electrode were used to prepare a low-cost MLA with a low sintering temperature of 900 °C. The MLA showed superior piezoelectric properties with d33 = 3015 pC/N and a large electric-field-induced strain of 0.13% at 22.2 kV/cm. Moreover, the stator of the ultrasonic motor composed of this MLA produced the ideal vibration mode, and the maximum rotation speed of the ultrasonic motor was 192 r/min under a 50 g load, which verifies the applicability of this component in practical minimised devices. These results demonstrate a strategy for fabricating low-cost and high-precision micro-actuators for precision driving.

BNT-based multi-layer ceramic actuator with enhanced temperature stability

The large temperature dependence of electro-strain for Bi0.5Na0.5TiO3 (BNT)-based ceramics limits their practical applications. In this work, Li-doped BNT-based lead-free multi-layer piezoelectric ceramic actuators are prepared by solid-state reaction synthesis method. The multi-layer actuator structure is fabricated by gradient doping, in which each layer corresponds to different compositions, with enhanced temperature stability compared to the single-layer one. For specific composition, it could achieve maximum electro-strain value at a certain temperature. Therefore, the electro-strain of each layer in this BNT-based multi-layer actuator could compensate each other at different temperatures with improved temperature stability. Consequently, the electro-strain of the five-layer structure varies less than ∼12% when the temperature changes from 50 °C to 130 °C, and a large electro-strain of 600 pm/V could be obtained at 70 °C. This work provides an effective approach by gradient doping to broaden the use temperature range for BNT-based actuators with improved temperature stability.

Characterization of Domains Reorientation in Multilayer Piezoelectric Ceramic Actuators by Polarized Raman Spectroscopy

Polarized Raman spectroscopy was applied to characterize domains reorientation in the multilayer piezoelectric ceramic actuators during the poling process and in the near crack tip zone. It is found that the relative intensity of the vibration modes of E(2TO) and E(3TO + 2LO) + B1 (IE(2TO)/Isilent) is affected by electric field and mechanical stress. During the poling process, IE(2TO)/Isilent increases when the applied DC electric field exceeds the coercive electric field. In the near crack tip zone, the IE(2TO)/Isilent mapping indicates that near the crack tip zone indicated that the domains were reoriented and the mapping of Raman shift of E(3TO + 2LO) + B1 mode reveals the stress release caused by crack development. This study also confirms that the relative intensity of IE(2TO)/Isilent can be used for characterization of domains reorientation in PZT‐based ceramics under electric and mechanical stresses.

Low-Temperature Sintered Pb(Zr,Ti)O3–Pb(Mn,Sb)O3–Pb(Zn,Nb)O3 for Multilayer Ceramic Actuators

A quaternary 0.90Pb(Zr0.48Ti0.52)O3–0.05Pb(Mn1/3Sb2/3)O3–0.05Pb(Zn1/3Nb2/3)O3 (0.90PZT–0.05PMS–0.05PZN) piezoelectric ceramic was synthesized by a conventional method, and CuO was adopted to lower its sintering temperature. The crystal structure, micromorphology, and electrical properties were studied in terms of CuO content. The results indicate that 1.0 wt % CuO addition significantly improves the sinterability of 0.90PZT–0.05PMS–0.05PZN ceramics, lowering the sintering temperature to 900 °C and maintaining moderate electrical properties: d33=306 pC/N, Qm=997, kp=53.6%, tan δ=0.50%, and ε33T/ε0=1350. The low-temperature sintering behavior could be explained by the formation of a transient liquid phase by CuO during sintering. Moreover, the endothermic peak at about 950 °C in the differential thermal analysis (DTA) curve of the raw ceramic powder provides further evidence of an amorphous phase. To obtain better piezoelectric properties, La2O3 was selected as the donor dopant for the 0.90PZT–0.05PMS–0.05PZN + 1.0 wt % CuO system. Our study demonstrates that La2O3 is very effective in improving piezoelectric properties, markedly increasing d33 and kp without decreasing Qm. Finally, 0.5 wt % La2O3 added 0.90PZT–0.05PMS–0.05PZN + 1.0 wt % CuO ceramics show excellent electrical properties: d33=355 pC/N, Qm=936, kp=58.4%, tan δ=0.32%, and ε33T/ε0=1590, which are quite suitable for multilayer piezoelectric ceramic actuators.

Modeling Multilayer Piezoelectric Actuators in a Residual Temperature Field

Electromechanical field concentrations near the electrodes in multilayer piezoelectric ceramic actuators in a residual temperature field are examined. The problem is formulated by considering a representative unit in the real multilayer actuators. A singular integral equation, in which the unknown function is the electric potential ahead of the electrode tip, is derived. The solution of the integral equation gives the electroelastic fields near the electrode tip. The thermally induced electric field ahead of the electrode tip is found to be highly singular. On the other hand, the stresses and electric displacements are singular behind the electrode tip. Possible debonding and cracking between the electrodes and the piezoelectric medium is investigated by energy density theory.

CrossRef Listing of Deleted DOIs

Multilayer piezoelectric ceramic displacement actuators are susceptible to cracking in the region near the edge of the internal electrode, which may cause system damage or failure. In this paper, the stress distribution of a multilayer piezoelectric composite is investigated in a working environment and the optimized geometrical configuration of the piezoelectric layer is obtained. The stress distribution in the structure and the stress concentration near the edge of the internal electrode, induced by non-uniform electric field distribution, are analyzed by moire interferometry experiment and finite element numerical simulation. Based on the above analysis, two optimized geometrical models are presented for the purpose of geometrical configuration selection, with which stress concentration can be reduced significantly while the feasibility of the machining process and the basic structural functions occurring in the conventional model are retained. The numerical results indicate that the maximum stress in the optimized models is effectively diminished compared to the conventional model. For instance, the peak value of the principal stress in the optimized model II is 93.1% smaller than that in the conventional model. It is proved that stress concentration can be effectively relaxed in the latter of the two optimized models and thus the probability of fracture damage can be decreased.

Nanoscale positioning for magnetic recording

A nanoscale positioning system for magnetic recording purpose has been designed and fabricated. A two-dimensional random-access of the sample is performed by inclining the two parallelograms with the aid of two multi-layer piezoelectric ceramic actuators. A so-called `displacement contracting' effect is used to enhance the positioning resolution. A positioning resolution of 1.6 nm with this stage has been achieved. This high-resolution, linearized and temperature-compensated system has the potential to address fundamental issues associated with recording at densities much greater than 10 Gbits/in 2 (1.5 Gbits/cm 2).

1016 積層形 PZT アクチュエータを利用した触覚呈示装置

This paper describes the virtual reality for tactile sensation. Since human beings grasp an object according to the surface condition and recognize material of the object, it is important for handling and inspecting objects that human beings recognize object surface. In virtual reality, the tactile sensation is important to enhance the reality of objects presented. Although, several tactile presentation devises have been reported so far, there are a few matrix-typed tactile presentation devises. Since human tactile receptors are distributed on entire fingertip surface, the matrix-typed tactile presentation device is essential to realize the virtual reality for tactile sensation. In this paper, multi-layer piezoelectric ceramic actuators were used for a pressure generator because they can control precise displacement. The single pressure stimulator is composed of four PZT ceramic actuators (displacement of a PZT ceramic actuator is 15 microns per 100 V) and a lever capable of enlarging displacement caused by the PZT ceramic actuators. A tactile presentation device was comprised of 2-by-2 pressure stimulators. To avoid vibration the tactile presentation device was mounted on an X-Y table using linear air-bearings. During experiments, six human subjects touched basic virtual figures such as a circle, a triangle and a square to obtain reasonable distance between two pressure points. From edge trace tests, we estmate the reasonable distance would exist between 1 and 2 mm.

An approach to enlarging the maximum bit in piezoelectric digital actuator

A digital actuator arrangement coded with driven numbers of piezoelectric ceramic pieces has been developed to improve nonlinear response, and hysteresis characteristics as well, in a multilayer piezoelectric ceramic actuator, and adopt it as a displacement device in precise mechanical systems. The proposed 8 bit actuator consists of two sets of conventional 4 bit units driven by different voltages. The experimental results indicate that the actuator works well, showing smooth and linear response.

Multilayer Piezoelectric Ceramic Actuator with Interdigital Internal Electrodes

A multilayer piezoelectric ceramic actuator with interdigital internal electrodes has been developed. The internal electrodes of this actuator are line electrodes which are printed on piezoelectric ceramic green sheets and stacked such that alternating electrode lines are displaced by one-half pitch. This actuator is displaced at right angles to the stacking direction due to the piezoelectric longitudinal effect. Therefore, it is possible to prepare a long ceramic actuator, which will be highly reliable in applications. In this work, we have obtained a displacement of 50 µm/DC350V and a generative force of 34.3 MPa for a 74-mm-long actuator. The reliability of this actuator is confirmed to have a long life of more than 1000 hours using applied voltage of DC350V at 25°C and 60%RH.

PdP136. Application of piezoelectric actuator to burr-free blanking

Abstract A high power, multilayer piezoelectric ceramic actuator has been developed and has been applied to burr-free blanking of thin foil using the reciprocating blanking method. A ternary system, Pb(Ni1/3Nb2/3O3-PbZrO3-PbTiO3, was selected for piezoelectric ceramics prepared using the conventional method. The following results were obtained from this study. (1) The maximum force and displacement of the actuator (D=35mm) induced by an applied voltage of 400V were 2. 8×104N and 50μm respectively. (2) It was possible to blank foil 13 – 80μm thick using piezoelectric ceramic actuators with this method, and obtain burr-free edges.

Recent developments in multilayer piezoelectric ceramic actuators and their applications

Abstract A new structure for multilayer piezoelectric ceramic actuators, called the slit structure, has been proposed and various applications for multilayer piezoelectric ceramic actuators, such as an impact dot-matrix printer head, an ultrasonic motor and a fine mechanical stage, have been investigated. The slit structure actuator is suitable for low driving voltages and it is easy to fabricate. The new printer head operates at twice the printing speed with less than 1/2 of the power consumption of a conventional electromagnetic drive printer head. The ultrasonic motor, composed of an actuator and a piezoelectric torsional mode resonator, exhibits large torque with small radius. The fine mechanical stage, for use in semiconductor manufacturing equipment, has 0.01 μm linear resolution and 0.9 μrad angular resolution, respectively.

Pulse Mode Operation for Piezoelectric Ceramic Actuator

Multilayer piezoelectric ceramic actuators were driven in large amplitude pulse modes by a new charge-discharge circuit with a series inductor. About 56% of the supplied electrical energy was recovered for the mechanically unloaded actuator. About 21% was lost as heat at the actuator. The maximum electro-mechanical energy conversion efficiency for the mechanically loaded actuator was 36%.

Multilayer Piezoelectric Ceramic Actuator with Varying Thickness Layers

A structure for a multilayer piezoelectric ceramic actuator has been studied using finite element method analysis for reducing stresses which are induced at an adhesive layer between the ceramic actuator and a certain body to which the actuator is attached. The stresses are induced by a piezoelectric unstiffened effect (or piezoelectric transverse effect) and they cause mechanical rupture of the adhesive layer. They are successfully reduced for the actuator with both piezoelectric inactive layers and layers which induce a small strain on its top and bottom. It was experimentally confirmed that no mechanical rupture occurs, when adopting an actuator with the improved structure.

Temperature Characteristics for Multilayer Piezoelectric Ceramic Actuator

Temperature characteristics for multilayer piezoelectric ceramic actuator have been investigated. Thermal expansion coefficient with DC 150 V application is negative, -6×10-6/°C, at 20°C. Between 0°C and 100°C, an available net displacement under DC 150 V is less changed, within 5%. Temperature rise and dissipation power due to dielectric loss were observed while driving at 0.3∼1.5 kHz. They are about 70°C and 0.7 J/sec at 1.5 kHz, with 150V peak voltage, respectively. The results suggest that a main origin for a temperature rise is dielectric loss.

Internal Electrode Piezoelectric Ceramic Actuator

An internal electrode multilayer piezoelectric ceramic actuator element has been investigated. An individual internal electrode has the same area as the element cross section area. It has no piezoelectric inactive part, so that it shows strain/field characteristics similar to plain piezoelectric ceramics. It can be driven by a relatively low voltage (200 V) and has a semipermanent life under a successive voltage pulse application. Typical properties of the element using 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 ceramics are 8.7×10-4 strain, over 3.5×107 N/m2 stress and within 100 µsec response time driven by 1×106 V/m field.