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Porous piezoceramics for medical and sensor applications
E. Ringgaard1*, T. Zawada1, F. Lautzenhiser2, E. Molz2, and L.M. Borregaard1
1
Meggitt Sensing Systems Denmark
Porthusvej 4, Kvistgaard, Denmark, DK-3490
2
Meggitt Sensing Systems Indiana
8431 Georgetown Road, Indianapolis, Indiana, IN 46268, USA
*e-mail: [email protected]
The use of porosity for modifying the functional properties of piezoelectric ceramics is well known in the
scientific literature as well as by the industry, and the porous ceramic can be seen as a 2-phase composite.
In the present work, examples are given of applications where controlled porosity is exploited in order to
optimise dielectric, piezoelectric and acoustic properties of the piezoceramics. For the optimisation effort it
is important to note that the thickness coupling coefficient kt will show a maximum for some non-zero
value of the porosity that could be above 20 %1. On the other hand, with a good approximation the acoustic
velocity decreases linearly with increasing porosity, which is obviously also the case for the density, and
consequently the acoustic impedance shows a rather strong decrease with porosity. For example, a porosity
of 30 % causes the acoustic impedance to drop to approximately 15 MRayl, which should be compared
with a value of 33 MRayl for standard FerropermTM Pz27 with about 4 % porosity. The significance of the
acoustic impedance is associated with the transmission of acoustic signals through the interface between
the piezoceramic and some medium of propagation, but when the porous ceramic is used as a substrate for
a piezoceramic thick film, the attenuation coefficient may be equally important. In case of open porosity it
is possible to introduce a liquid into the pores, and examples of modifying the properties in this way are
given.
1. Measurements of the thermal, dielectric, piezoelectric, pyroelectric and elastic properties of porous PZT
samples, Lang SB and Ringgaard E, Appl.Phys. A, 117, 631-638 (2012).
Short CV - Erling Ringgaard, Meggitt A/S
Working address
Meggitt A/S
Porthusvej 4
DK-3490 Kvistgård
((+45) 49 12 71 24
[email protected]
Personal data
Date of birth:
Citizenship:
30th April 1968
Danish
Education
1994
1999
Master of science in chemistry. Final project at Dept. of Mineral Industry,
DTU
PhD degree from Dept. of Chemistry, DTU, in materials science
Employment
2012-
Principal Materials Scientist at Meggitt A/S.
1999-2012 Employment at Meggitt A/S (formerly Ferroperm Piezoceramics A/S) as
project manager. Work primarily with EU and Danish (Højteknologifonden,
HTF) research projects, including as coordinator.
1994-1999 Part-time employment at Ferroperm Piezoceramics A/S (25 %, concurrent
with Ph.D. project). Work in research and development related to EU
projects.
Project management
EU projects ECITA (1994-1997, Ct. No. BRE2 1008), internally responsible
TIFFANI (1997-1999, Ct. No. BRPR960318), internally responsible
PIMET (1997-2000, Ct. No. Σ!1664), internally responsible
PICROP (1999-2002 Ct. No. Σ!2037;), internally responsible
LEAF (2001-2004, Ct. No. G5RD-CT2001-00431), general coordinator
PIRAMID (2001-2004, Ct. No. G5RD-CT2001-00456), internally responsible
MINUET (2004-2007, Ct. No. NMP2-CT2004-505657), general coordinator
AISHA II (2008-2011, Ct. No. AAT-2007-212912), internally responsible
DK projects Π-MEMS (2006-2009, HTF j.nr. 009-2005-1), steering committee chairman
ELBA (2009-2013, HTF j.nr. 036-2009-1), internal project manager