Low shear compounding process for thermoplastic fabrication of ferroelectric lead-free fibres

Lusiola, Tony; Scharf, Dagobert; Graule, Thomas; Clemens, Frank

doi:10.1016/j.jeurceramsoc.2014.02.036

Cited by 10 publications

(9 citation statements)

References 27 publications

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“…In comparison to KNN fibers [16], the electromechanical properties can be improved using KNNT with tantalum as a B-site substituent for fiber production. The low coercive field and high dielectric constant make them interesting for lead-free-based actuator applications.…”

Section: Discussionmentioning

confidence: 99%

“…Green fibers were obtained by extruding the feedstock vertically with a capillary rheometer (RH7 Flowmaster, Rosand Precision Ltd., Stourbridge, UK) through a 300-and 500-µm die, at 106 °C and a shear rate of 500 s −1 , with an adapter to reduce the diameter of the cylinder from 24 mm-4 mm. More details about the fiber production can be found in Lusiola et al [16].…”

Section: Methodsmentioning

confidence: 99%

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Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

et al. 2015

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B-site substitution in KNN with tantalum results in a higher d33 and dielectric constant. This higher value makes KNNT interesting for lead-free actuator applications. KNNT fibers with diameters of 300 and 500 μm have been extruded and sintered at 1200 °C in a KNNT-enriched atmosphere. Subsequently, the influence of fiber diameter on the microstructure (porosity and grain size) was investigated. The measurements revealed that with decreasing fiber diameter, the porosity increases, whereas the grain size decreases. The influence of these microstructural differences on the piezoelectric properties was evaluated using a novel characterization procedure for single fibers. The larger diameter fibers show an increase in the electromechanical properties measured, i.e., d33, tanδ, Pr, Ec and the free longitudinal fiber displacement, when compared to smaller diameter fibers. The lower alkali losses result in a larger grain size, a higher density during sintering and lead to higher electromechanical properties. OPEN ACCESSActuators 2015, 4 100

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

et al. 2015

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“…All samples were partially electroded with silver paste (Electrodag 5195, Henkel GmbH, Erlinsbach, Switerland) on top and bottom and fired at 150 • C for 15 min to avoid the arcing around the electrodes. The measurements were carried out using the piezoelectric evaluation system aix PES (aixACCT systems GmbH, Aachen, Germany); the details of this setup have been described elsewhere [29][30][31]. A schematic of the instrument is shown in Figure 2.…”

Section: Methodsmentioning

confidence: 99%

Investigation of Electromechanical Properties on 3-D Printed Piezoelectric Composite Scaffold Structures

et al. 2021

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Piezoelectric composites with 3-3 connectivity gathered attraction due to their potential application as an acoustic transducer in medical imaging, non-destructive testing, etc. In this contribution, piezoelectric composites were fabricated with a material extrusion-based additive manufacturing process (MEX), also well-known under the names fused deposition modeling (FDM), fused filament fabrication (FFF) or fused deposition ceramics (FDC). Thermoplastic filaments were used to achieve open and offset printed piezoelectric scaffold structures. Both scaffold structures were printed, debinded and sintered successfully using commercial PZT and BaTiO3 powder. For the first time, it could be demonstrated, that using the MEX processing method, closed pore ferroelectric structure can be achieved without pore-former additive. After ceramic processing, the PZT scaffold structures were impregnated with epoxy resin to convert them into composites with 3-3 connectivity. A series of composites with varying ceramic content were achieved by changing the infill parameter during the 3D printing process systematically, and their electromechanical properties were investigated using the electromechanical aix PES device. Also, the Figure of merit (FOM) of these composites was calculated to assess the potential of this material as a candidate for transducer applications. A maximum for the FOM at 25 vol.% of PZT could be observed in this study.

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“…[17] In this contribution, BT macrofibers were fabricated using thermoplastic ceramic processing. [18][19][20] Due to their high intrinsic properties, BT nanofibers have been employed as ferroelectric fillers in the nanocomposites to improve the final dielectric properties while typically a polymer material is used as the matrix. The effect of BT nanofibers in ferroelectric macro structures has not been investigated so far.…”

Section: A C C E P T E D Mmentioning

confidence: 99%

“…A low shear mixing process, developed at Empa, was used for the thermoplastic extrusion of BaTiO3 macrofiber. [19,20] All feedstocks were formulated with 30 vol% of BT powder (Ticon F, Ferro Electronic Materials, Niagara Falls, NY, USA) and 20 vol% BT nanofibers calcined at different temperatures, along with 40 vol% thermoplastic binder, ethylene-vinyl acetate…”

Section:  Macrofiber Fabricationmentioning

confidence: 99%

Enhancing dielectric properties of barium titanate macrofibers

Sebastian

Michalek

Hedayati

et al. 2019

Journal of the European Ceramic Society

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The motivation of this work was to improve the dielectric properties of BaTiO3 (BT) macrofibers by mixing BT nanofibers and commercial BT powder. BT nanofibers were fabricated via electrospinning synthesis. The calcined electrospun nanofibers were chopped and mixed with BT powder and converted in to a thermoplastic feedstock for extrusion of ceramic macrofibers with a diameter of 500 μm. The electromechanical properties of the BaTiO3 macrofibers were investigated by varying calcination temperature of the nanofibers. For both nano and macro fibers, microstructure and phase composition was investigated by SEM and XRD. It could be observed that an increase in calcination temperature of the nanofibers enhanced the final electromechanical properties of the sintered macrofibers. The relative permittivity increased almost twice, the remanent polarisation increased about 4 times and the strain almost increased 10 times with the addition of calcined nanofibers to macrofibers.

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Low shear compounding process for thermoplastic fabrication of ferroelectric lead-free fibres

Cited by 10 publications

References 27 publications

Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

Investigation of Electromechanical Properties on 3-D Printed Piezoelectric Composite Scaffold Structures

Enhancing dielectric properties of barium titanate macrofibers

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