A5052612980- Acoustic Wave Resonator Technologies
- Ferroelectric and Piezoelectric Materials
- Ultrasonics and Acoustic Wave Propagation
- Ultrasound Imaging and Elastography
- Microwave Dielectric Ceramics Synthesis
- Acoustic Wave Phenomena Research
- Advanced Sensor and Energy Harvesting Materials
- Multiferroics and related materials
- Dielectric materials and actuators
- Photoacoustic and Ultrasonic Imaging
- Ultrasound and Hyperthermia Applications
- Advanced MEMS and NEMS Technologies
- Wireless Power Transfer Systems
- Energy Harvesting in Wireless Networks
- Innovative Energy Harvesting Technologies
- Electrical and Thermal Properties of Materials
- Thermography and Photoacoustic Techniques
- Adhesion, Friction, and Surface Interactions
- Liquid Crystal Research Advancements
- Engineering Applied Research
- Neuroscience and Neural Engineering
- Optical Coherence Tomography Applications
- Electrical and Bioimpedance Tomography
- Smart Materials for Construction
- Photorefractive and Nonlinear Optics
Meggitt (Denmark)
2010-2022
Université de Tours
2005
The use of porosity to modify the functional properties piezoelectric ceramics is well known in scientific literature as by industry, and porous ceramic can be seen a 2-phase composite. In present work, examples are given applications where controlled exploited order optimise dielectric, acoustic piezoceramics. For optimisation efforts it important note that thickness coupling coefficient kt will maximised for some non-zero value could above 20%. On other hand, with good approximation,...
Solid solutions of BiFeO3 and BaTiO3 are promising lead-free piezoelectric materials, especially around the morphotropic phase boundary at 0.67BiFeO3-0.33BaTiO3. Still, these materials challenged by instability limited understanding processing-properties relationship. Here, we investigate mechanochemical activation use as seed particles for 0.67BiFeO3-0.33BaTiO3 phase. Contrary to expectations from seeding in lead-based perovskites, seeds do not promote perovskite neither during nor...
Detection of high-order nonlinear components issued from microbubbles has emerged as a sensitive method for contrast agent imaging. Nevertheless, the detection these high-frequency components, including third, fourth, and fifth harmonics, remains challenging because lack transducer sensitivity bandwidth. In this context, we propose new design imaging based on simple fabrication process The is composed two elements: outer low-frequency (LF) element was centered at 4 MHz used in transmit mode,...
Abstract Piezoelectrics are key materials for energy conversion, example in ultrasound transducers and harvesters. This work presents the synthesis characterization of lead-free piezoelectric composition (Li 0.06 (K 0.52 Na 0.48 ) 0.94 )(Nb 0.71 Ta 0.29 )O 3 doped with 0.25 mol% Mn (KNNLTM) as textured ceramics. Templated grain growth from NaNbO platelet templates aligned by tape casting was used to introduce texture, after sintering 14 h at 1100 °C this produced up 84% (100) pc orientation....
The market for piezoceramic components is dominated by lead zirconate titanate (PZT) materials containing more than 60 wt% lead. Since a toxic heavy metal, it has become great concern how to eliminate the use of PZT replacing non-harmful while maintaining comparable piezoelectric properties. This was objective European LEAF project within GROWTH programme, ending in February 2004. In this project, alkali niobates were proposed as alternative materials, and special emphasis given potassium...
A new innovative multilayer PT design for operation with high power density and frequencies up to several MHz is presented. The based on a ring-shaped element operating in thickness vibrational mode, where the primary secondary sides are separated by an isolation layer. Prototypes intricate geometry, result of FEM simulations maximising effective coupling factor working mode suppressing spurious modes, Initial results show densities above 40 W/cm/sup 3/ at efficiencies 98%. This clear...
Non-linear increases in elastic, piezoelectric (direct and reverse) dielectric coefficients have been measured under a high electrical field or mechanical stress. The permittivity reverse coefficient can be by applying voltage at low frequency, while the elastic compliance direct first radial resonance frequency order to apply non-linear behaviour has analysed of disc.In all materials tested, results show that there is close relation between increments different coefficients. An empirical...
Energy harvesting, known also as energy scavenging, covers a great body of technologies and devices that transform low grade sources such solar energy, environmental vibrations, thermal human motion into usable electrical energy. In this paper vibrations are used source transformed by the harvesting micro-generator signal. The comprises silicon cantilever with integrated InSensor® TF2100 PZT thick film deposited using screen-printing. output power versus frequency load has been investigated....
Research activities on lead-free piezoelectric materials have been ongoing for over twenty years. Generally, the applicability of main material families is less universal than that lead-based compositions such as lead zirconate titanate, but in some cases corresponding applications already identified. Thanks to extensive research it now possible manufacture demonstrators and prototypes different authors propose this article take stock these advances. For this, we chosen first recall briefly...
High energy synchrotron XRD was employed to determine the lattice strain ε{111} and diffraction peak intensity ratio R{200} in tetragonal PZT ceramics, both virgin poled state after a bipolar fatigue experiment. It shown that occurrence of microstructural damage during accompanied by reduction gradient ε{111}–cos2 ψ plot, indicating level residual stress due poling. In contrast, fraction oriented 90° ferroelectric domains, quantified terms R{200}, not affected significantly fatigue. The...
The structural evolution of a polydomain ferroelectric Pb(Zr0.2Ti0.8)O3 film was studied by temperature-dependent x-ray diffraction. Two critical temperatures were evidenced: T*=740K, corresponding to change in the domain structure (a∕c∕a∕c a1∕a2∕a1∕a2), and TCfilm=825K, where undergoes ferroelectric-paraelectric phase transition. remains tetragonal on whole range temperature investigated. evolutions lattice parameters found be very good agreement with calculated stability map theoretical...
The purpose of this paper is to present the comparative study a single-element transducer based on KNN and lead-based ceramics. A thickness coupling coefficient 35%, sound velocity 5800 m/s dielectric constant 280 are found make material suitable for medium high frequency applications. On basis these electromechanical properties, we have used KLM model predict electroacoustic behaviour 10 MHz with two matching layers. We show that transducers performances intermediate between those PT-based...
This paper describes a new ceramic-air piezocomposite material, ie. porous piezoceramic based on soft PZT matrix. First, the microstructure is analyzed and electromechanical parameters are measured, in particular dielectric constant, acoustic wave velocity mechanical losses, acoustical impedance thickness mode coupling factor. Among these parameters, frequency dependence investigated experimentally using complex measurements at fundamental harmonic frequencies of free resonance mode. A...
The introduction of porosity into ferroelectric ceramics has been great interest in recent years. In particular, studies porous lead-zirconate-titanate ceramic (PZT) have made. the research reported, samples Ferroperm Pz27 with porosities 20, 25 and 30% were studied. Very complete measurements made all physical properties relevant for applications including thermal conductivity diffusivity, heat capacity, dielectric, pyroelectric, piezoelectric elastic properties. Scanning electron...
A direct comparison of performance and acoustic properties high intensity focused ultrasonic transducers utilizing lead-free (Sodium Bismuth Titanate - NBT) lead-based (Lead Zirconate PZT) piezoceramics is discussed. All operate at 12 MHz third harmonic frequency, having an outer diameter 20 mm, a central hole 5 mm in radius curvature 15 mm. The electro-acoustic efficiency determined by radiation force balance evaluated range input power levels up to W. Schlieren tomography as well...