Lead zirconate titanate

About: Lead zirconate titanate is a research topic. Over the lifetime, 7141 publications have been published within this topic receiving 150878 citations.

Electrical Resistivity of Lead Zirconate Titanate Ceramics Containing Impurities

Abstract: Electrical resistivity and its temperature variation are measured for lead zirconate titanate ceramics containing various metal oxides as impurities. The impurities can be classified from their influence on the resistivity of ceramics into the following three groups. (1) Impurities which keep the resistivity nearly unchanged (e.g. Fe2O3). (2) Impurities which increase it enormously because of electron-hole compensation (e.g. Nb2O5). (3) Impurities which increase it at first (electron-hole compensation) and then decrease it (e.g. Cr2O3). The decrease of resistivity in group (3) seems to be caused by the generation of segregated impurity layers which enclose the grains in ceramics. This postulate is confirmed quantitatively by the measurements of resistivity of the ceramics in which impurities are injected by means of thermal diffusion.

Demonstration and characterization of PZT thin-film sensors and actuators for meso- and micro-structures

Abstract: Recent development of next-generation medical devices, such as endoscopes and hearing aids, call for PZT (lead zirconate titanate oxide) thin-film sensors and actuators with thickness in the range of 1–30 μm to enhance actuation strength and sensor sensitivity. Currently, sol–gel derived PZT films often have thickness less than 0.2 μm per coating. Moreover, thermal stresses in the films limit the crack-free area to less than 1 mm2. This paper has four specific goals. The first goal is to demonstrate an improved sol–gel process using rapid thermal annealing and a diluted sealant coating. The resulting thickness can reach 2 μm in three coatings with a crack-free area as large as 5 mm ×5 mm . The second goal is to characterize piezoelectric properties of the fabricated PZT films experimentally. The resulting piezoelectric constant d33 is 120 pC/N and the dielectric constant ranges from 200 to 400. The third goal is to demonstrate the use of the PZT thin film as a calibrated sensor. The specimen is a silicon cantilever ( 30 mm ×7.5 mm ×0.4 mm ) with a PZT thin film ( 4 mm ×4 mm ×1 μm ). Moreover, a tiny shaker excites the cantilever at the fixed end, and a charge amplifier detects the charge accumulated in the PZT film. In the meantime, a laser vibrometer measures the deflection of the cantilever at three points along the PZT film, from which the strain is calculated using Euler–Bernoulli beam theory. Comparison of the strain and the charge amplifier voltage determines the calibration constant of the PZT thin-film sensor. The last goal is to demonstrate the use of the PZT thin film as a powerful actuator through active vibration control. In experiments, a tiny bulk PZT patch is first glued to the silicon cantilever. A function generator drives the bulk PZT simulating a source of disturbance exciting the silicon cantilever. In the meantime, a laser Doppler vibrometer (LDV) measures velocity of the cantilever tip. With a phase shifter as the controller, the LDV measurement is fed back to the PZT thin-film actuator to actively control the cantilever vibration. To evaluate the effectiveness of the active vibration control, a spectrum analyzer measures the frequency response functions (FRF) from the bulk PZT voltage to the LDV response. Experimental results show that the simple active vibration control scheme can reduce resonance amplitude of the first bending mode by 66%.

PZT ‘composite’ ferroelectric thick films

Abstract: Thick-films of lead zirconate titanate ceramic have been fabricated at low-temperature using a modified sol-gel/ceramic powder technology termed the composite technique. In this process, a ferroelectric powder is suspended in an organometallic solution of the same composition, which is deposited either on metallic or platinised silicon substrates using spin-coating. Dielectric properties have been improved from values around 450–680 by incorporating a novel Cu 2 O/PbO liquid-phase sintering aid. Rheology studies were carried out to monitor ageing of both the organometallic solution and composite suspension. Over a trial period of 41 days, the organometallic solution was shown to remain stable. Tests further indicated solution stability down to −20°C. Such low temperatures may be experienced during transportation in large-scale manufacturing. By modelling such thick films as 0–3 composites, it is known that electric properties are enhanced with greater powder:solution ratio. This necessary greater loading has been achieved by adjusting the pH of the organometallic solution, allowing the zeta-potential developed on suspended particles to be increased. This considerably lowers the viscosity of the composite suspension and hence allows much greater powder loading. In this way, loadings of up to 2.5 g/ml have been achieved. Optimum permittivities and losses in sintered films of up to 680 and 0.01 have been measured on films 16 μm thick, with associated spontaneous polarisation of 19.8 μC/cm 2 with 1.6 V/μm applied.

Electrical and mechanical properties of piezoelectric ceramic/metal composites in the Pb(Zr, Ti)O3/Pt system

Abstract: As a model for composite materials of piezoelectric ceramic and metal, lead zirconate titanate (PZT) and platinum (Pt) particulate composites were fabricated by power processing. The electrical and mechanical properties of the PZT–Pt composites were measured as a function of the Pt volume fraction. The relative dielectric constants of the PZT–Pt composites increased markedly, while the piezoelectric constants and electromechanical coupling coefficients decreased with increasing Pt content. When the Pt volume fraction exceeded 30%, the PZT–Pt composite became electrically conductive because of percolation of the Pt particles. The Pt-dispersed PZT composites enhanced the mechanical properties, particularly the high fracture resistance, compared to the monolithic PZT ceramics.