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ABSTRACT: The Micropen™ direct-write technique was used to fabricate ceramic skeletal structures to develop piezoelectric ceramic/polymer
composites with 2–2 connectivity for medical imaging applications. A lead zirconate titanate PZT paste with ∼35vol.% solids
loading was prepared as a writing material and the paste’s rheological properties were characterized to evaluate its feasibly
for Micropen deposition. A serpentine pattern was designed and deposited in AutoCAD and with a 100μm pen tip, respectively.
After debinding and sintering, the microstructural analysis showed that the ceramic structures were fully densified, with
good bonding among layers. Typical single-layer thickness was ∼50μm, and sintered line width was ∼120μm. The composites
containing 30–45vol.% PZT were fabricated within 1cm2 area, with thicknesses ranging from 350 to 380μm. Their electromechanical and dielectric properties were measured and found
similar to that of composites fabricated by other techniques. The k
t was ∼0.61, d
33 was 210–320, with Q
m of ∼6 and dielectric constant of 650–940.
KeywordsDirect-write-Composites-Piezoelectric properties-PZT
Journal of Electroceramics 04/2012; 24(3):219-225. · 1.19 Impact Factor
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ABSTRACT: We present a new type of actuator named bilayer piezoelectric/electrostrictive dome unimorph (BIPEDU), fabricated by attaching a piezoelectric-electrostrictive monolithic bilayer composites (PE-MBLC) to a metal plate. Various ratios of piezoelectric/electrostrictive (P/E) volume percent were used to form PE-MBLC. It was found that d<sub>33</sub> <sup>eff</sup> and K<sup>eff</sup> in PE-MBLC follow the series 2-2 composite mixing rule. However, the measured results were slightly lower than those of the calculated values because of a large difference in dielectric displacement between piezoelectric and electrostrictive layers and because the electrostrictor acts as the resistor that impedes the domain switching in piezoelectric layer during poling. In addition, we have investigated the field-induced displacement in PE-MBLC and BIPEDU actuators. In comparison, the displacement of BIPEDU actuators was much higher than that of PE-MBLC actuators. This was attributed to the good quality of bonding between ceramic and metal, which contributed to the proper stress/force transfer, as well as the metal sheet, which acted as a flextentional structure for PE-MBLC to generate more axial displacement in BIPEDU actuators. The load dependence of displacement in BIPEDU was obtained. In addition, the BIPEDU showed high reliability during the displacement cyclic testing.
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 01/2010; · 1.69 Impact Factor
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ABSTRACT: We propose a new type of flextensional actuator comprised of an electromechanically active element which is a piezoelectric-electrostrictive monolithic bi-layer composite (PE-MBLC) capped by truncated thin brass sheets. The PE-MBLC contains equal amounts of 0.65{Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>}-0.35PbTiO<sub>3</sub> and 0.9{Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>}-0.1PbTiO<sub>3</sub> by volume, and is obtained by a co-sintering process. With applied E<sub>max</sub> = 10 kV/cm unipolar drive, the maximum axial displacement (u<sub>33</sub>) produced by the uncapped and capped PEMBLC is 11 and 21 mum, respectively. The hysteresis in unipolar u<sub>33</sub> at 0.5 E<sub>max</sub> is 4.6% for the uncapped PE-MBLC, while that for the capped one is 11%. Under bipolar excitation, the maximum u<sub>33</sub> for uncapped is 11.6 mum at +E<sub>max</sub> and 6.6 mum at -E<sub>max</sub> with an asymmetry factor (xi)of 1.75 for which u<sub>33</sub> < 0 for all E < 0. Under bipolar excitation, the maximum u<sub>33</sub> at +E<sub>max</sub> for the capped PE-MBLC is 19 mum while that for -E<sub>max</sub> is 8 mum with xi = 2.4, for which u<sub>33</sub> > 0 at +E<sub>max</sub> but is smaller than the u<sub>33</sub> at +E<sub>max</sub>. The origins of the observed asymmetry in u<sub>33</sub> are discussed in the context of symmetry superposition and deformation mechanics of the endcaps.
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 07/2009; · 1.69 Impact Factor
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ABSTRACT: We examine the electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites with various piezoelectric volume percentage obtained by cosintering piezoelectric 0.65 Pb ( Mg <sub>1/3</sub> Nb <sub>2/3</sub>) O <sub>3</sub>-0.35 PbTiO <sub>3</sub> and electrostrictive 0.9 Pb ( Mg <sub>1/3</sub> Nb <sub>2/.3</sub>) O <sub>3</sub>-0.1 PbTiO <sub>3</sub> under unipolar and bipolar electric field excitation up to 10 kV/cm experimentally. It is shown that the effective d<sub>33</sub> of the composites is limited by the electrostrictive layer, which acts as a capacitor in series to the piezoelectric layer, causing incomplete poling. We show that by controlling the volume content of the piezoelectric layer and constraining it with an electrostrictor, substantial strain amplification ( 15 μ m for bipolar excitation) can be achieved while inducing asymmetry to the displacement with respect to the polarity of the applied field, which we discuss in the context of symmetry superposition.
Journal of Applied Physics 03/2009; · 2.17 Impact Factor
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ABSTRACT: We propose a new type of flextensional actuator comprised of an electromechanically active element which is a piezoelectric-electrostrictive monolithic bi-layer composite (PE-MBLC) capped by truncated thin brass sheets. The PE-MBLC contains equal amounts of 0.65[Pb(Mg(1/3)Nb(2/3))O(3)]-0.35PbTiO(3) and 0.9[Pb(Mg(1/3)Nb(2/3))O(3)]-0.1PbTiO(3) by volume, and is obtained by a co-sintering process. With applied E(max) = 10 kV/cm unipolar drive, the maximum axial displacement (u(33)) produced by the uncapped and capped PE-MBLC is 11 and 21 microm, respectively. The hysteresis in unipolar u(33) at 0.5 E(max) is 4.6% for the uncapped PE-MBLC, while that for the capped one is 11%. Under bipolar excitation, the maximum u(33) for uncapped is 11.6 microm at +E(max) and 6.6 microm at +E(max) with an asymmetry factor (zeta) of 1.75 for which u(33) < 0 for all E < 0. Under bipolar excitation, the maximum u(33) at +E(max) for the capped PE-MBLC is 19 microm while that for -E(max) is 8 microm with zeta = 2.4, for which u(33) > 0 at -E(max) but is smaller than the u(33) at +E(max). The origins of the observed asymmetry in u(33) are discussed in the context of symmetry superposition and deformation mechanics of the endcaps.
IEEE transactions on ultrasonics, ferroelectrics, and frequency control 02/2009; 56(6):1131-8. · 1.80 Impact Factor
