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.com
Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Ceramics 2018
May 14-15, 2018
May 14-15, 2018 | Rome, Italy
4
th
International Conference and Expo on
Ceramics and Composite Materials
Fabrication and characterisation of high-frequency ultrasonic transducers based on piezoelectric
thick films and porous backing
Danjela Kuscer
1
, Tina Bakarič
1
, Silvo Drnovšek
1
, Barbara Malič
1
, Julien Bustillo
2
and
Franck Levassort
2
1
Jozef Stefan Institute, Slovenia
2
François Rabelais University, France
T
he properties of the high-frequency transducer (>20 MHz), in particular its operating frequency, sensitivity and resolution,
are defined by the geometry, microstructure and characteristics of piezoelectric material and backing. For the backing,
acoustical impedance and attenuation coefficient are predominant properties to be determined. In this work, we proposed a
novel method for the in-situ measuring of these backing’s properties at the operating frequency of the transducer.
We report on the processing and characterization of lead-zirconate-titanate based (PZT) piezoelectric thick films on a porous
backing with tailored amount, size and shape of the pores. As a porous backing we used ~5mm-thick ceramic with nominal
compositionPb(Zr
0.53
Ti
0.47
)O
3
(PZT).Theceramicwaspreparedbyhetero-coagulationprocessofPZTandpolymethilmetacrylate
in water at pH 8 followed by sintering the powder compacts at 1080
o
C. Ceramic exhibited homogeneous microstructure with
15 % porosity and spherical, ~1 and ~10
µ
m-sized pores, respectively. The PZT thick films, screen-printed onto the electroded
backing and sintered at 900
o
C, had a thickness of ~25
µ
m, porosity of 20 % and thickness coupling coefficient of 45 %.
This integrated piezoelectric structure allows direct acoustic measurements of transducer components. The PZT thick film is
electrically excited to measure the electroacoustic response in water and also the back-wall echoes coming from the backing if
its thickness is sufficiently thin. The thickness of the backing was successively reduced and the measurements were repeated.
In the frequency range 15-25 MHz, the attenuation coefficients of backings with 1- and 10-
µ
m- sized pores were 0.7 dB/
mm/MHz and 4 dB/mm/MHz, respectively, the group velocities were ~3400 m/s which results in the acoustic impedance of
~22 MRa. The high attenuation in backing with 10
µ
m-sized pores and moderate acoustical impedance enable substantial
miniaturisation of high-resolution ultrasonic imaging transducers.
Recent Publications
1. Kuscer D, Rojac T, Belavič D, Santo Zarnik M, Bradeško A, Kos T, Malič B, Boerrigter M, Martin DM, Faccini M
(2017). »Integrated piezoelectric vibration system for fouling mitigation in ceramic filtration membranes«. J. Membr.
Sci., 540:277-284.
2. Mercier H, Malič B, Uršič H, Hreščakk J, Levassort F, Kuscer D (2017). »Electrophoretic deposition and properties of
strontium-doped sodium potassium niobate thick films«. J. Eur.Ceram. Soc., 37[16] : 5305-5313.
3. Bakarič T, Rojac T, Abellard AP, Malič B, Levassort F, Kuscer D, (2016). »Effect of pore size and porosity on piezoelectric
and acoustic properties of Pb(Zr0.53Ti0.47)O3 ceramics«. Adv. Appl. Ceram., 115 [2]: 66-71.
4. Kuscer D, Bernardo M, Santo Zarnik M, Malič B (2016). »Patterning of lead-zirconate-titanate thick-film structures by
electrophoretic deposition from ethanol-based dispersions«. J. Eur.Ceram. Soc., 36 [2]: 291-297.
5. Bakarič T, Malič B, Kuscer D (2016). »Lead-zirconate-titanate-based thick-film structures prepared by piezoelectric
inkjet printing of aqueous suspensions«. J. Eur.Ceram. Soc., 36 [16]: 4031-4037.
6. Abellard AP, Kuscer D, Gregoire JM, Malič B, Levassort F (2014). »Lead zirconate titanate-based thick films for high-
frequency focused ultrasound transducers prepared by electrophoretic deposition«. IEEE transactions on ultrasonics,
ferroelectrics, and frequency control, 61 [3]: 547-556.
7. Kuscer D, Noshchenko O, Uršič H, Malič B (2013). »Piezoelectric properties of ink-jetprinted lead zirconate titanate
thick films confirmed by piezoresponse force microscopy«. J. Am.Ceram. Soc., 96 [9]: 2714-2717.
Danjela Kuscer et al., Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C1-014