Piezoelectric and dielectric properties of (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3–PVDF composites (original) (raw)
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Journal of Advanced Ceramics, 2016
Polymer nanocrystal composites were fabricated by embedding polyvinylidene fluoride (PVDF) with K 0.5 Na 0.5 NbO 3 (KNN) nanocrystallites of different volume fraction using the hot-pressing technique. For comparison, PVDF-KNN microcrystal composites of the same compositions were also fabricated which facilitated the studies of the crystallite size (wide range) effect on the dielectric and piezoelectric properties. The structural, morphological, dielectric, and piezoelectric properties of these nano and micro crystal composites were investigated. The incorporation of KNN fillers in PVDF at both nanometer and micron scales above 10 vol% resulted in the formation of polar β-form of PVDF. The room temperature dielectric constant as high as 3273 at 100 Hz was obtained for the PVDF comprising 40 vol% KNN nanocrystallites due to dipole-dipole interactions (as the presence of β-PVDF is prominent), whereas it was only 236 for the PVDF containing the same amount (40 vol%) of micron-sized crystallites of KNN at the same frequency. Various theoretical models were employed to predict the dielectric constants of the PVDF-KNN nano and micro crystal composites. The PVDF comprising 70 vol% micron-sized crystallites of KNN exhibited a d 33 value of 35 pC/N, while the nanocrystal composites of PVDF-KNN did not exhibit any piezoelectric response perhaps due to the unrelieved internal stress within each grain, besides the fact that they have less domain walls.
Current Applied Physics, 2016
In this contribution, a promising environmentally friendly lead-free ferroelectric/polymer 0-3 composite, using polyvinylidene fluoride and barium sodium titanate niobate compounds, was synthesized and structurally and dielectrically characterized. The results suggest the complete formation of a 0-3 connected composite with enhanced dielectric properties, reaching a relative permittivity of 32 and a dissipation loss of 4%, at 1 kHz and 300 K, respectively. These dielectric features are associated with the intimate contact between the polymer and ceramic fraction in the composite that lead to the increase of the polar b-phase amount in the polymer fraction, at room temperature.
Structural, dielectric and piezoelectric properties of 0–3 PZT/PVDF composites
Piezoelectric composite films of ([PZT]x/[PVDF]1-x) with 0–3 connectivity were prepared using a solution cast technique. The films with different volume fractions of PZT ceramics in the morphotropic phase boundary were prepared in the form of thin films for the optimized thermal processing conditions. It is seen that the increase in the content of PZT ceramic in the PVDF matrix not only increases the dielectric constant of the composites but also enhances the β phase in the PVDF polymer, thereby resulting in the overall improved dielectric and piezoelectric behavior of the system. The as-synthesized films exhibited superior dielectric and piezoelectric properties than reported in the literature.
Ceramics International, 2017
Lithium chromium nickel oxide (Li 0.30 Cr 0.10 Ni 0.60 O, LCNO) materials were prepared by sol-gel process and calcined at the temperature of 1000°C for 3 h. Mechanical mixing process and hot pressing fabricated the composites between LCNO and polyvinylidene fluoride (PVDF). Effects of the amount of LCNO filler on the structure and dielectric properties of LCNO/PVDF composites were investigated. The LCNO/PVDF composites were characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), Xray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Furthermore, the dielectric properties of the LCNO/PVDF composites were also investigated. From TGA results, the decomposition step of LCNO/PVDF composites depends on the LCNO content and weight loss decrease with increasing LCNO contents due to the presence of LCNO in PVDF. All LCNO/PVDF composites exhibited two-phase structures of cubic rock-salt NiO structure and α-, γphases of PVDF. It is revealed that dielectric constant of the polymer composite increases with increasing LCNO content. This might be due to the formation of micro-capacitor network. The LCNO/PVDF composite with amount of 30 wt% showed the best properties with a high dielectric constant of 59.27 and low loss tangent of 0.31 at the frequency of 1 kHz and at room temperature. The composite gave a high dielectric constant, which was 2.82 times higher than that of pure PVDF. Therefore, the flexible high dielectric constant and low loss tangent of the composite were weakly frequency dependent, which might be suitable for capacitor applications.
Ferroelectric, Piezoelectric and Dielectric Properties of Novel Polymer Nanocomposites
Multifunctional Ferroelectric Materials, 2021
In this chapter, the Ferroelectric, Piezoelectric and Dielectric behavior of novel polymer/ceramic nano-composite (PCC) based on ferroelectric polymer [polyvinyledene fluoride (PVDF)] & nano Barium Titanate (n-BaTiO3) with different volume fractions of n-BaTiO3 (fBaTiO3), prepared through the novel cold pressing method has been discussed. The ferroelectric parameters of PCC are attributed to spherulites of PVDF, the increase of n-BaTiO3 and the ordered homogenous structure due to the novel cold pressing. The clustering of ceramic fillers is responsible for randomization of the structures of these composite ferroelectrics for some samples, leading to decrease of electrical polarisations. The piezoelectricity and piezoelectric coefficients of these composites ferroelectrics, increases with increase of ceramic filer content and remains constant beyond a certain ratio. However, the dielectric properties increase linearly as a function of ceramic content due to increase of interfaces/int...
Journal of Materials Science, 2017
PVDF-modified 0-3 connectivity cement-based/lead-free 0.94(Bi 0.5 Na 0.5)TiO 3-0.06BaTiO 3 piezoelectric ceramic composites were fabricated using 0.94(Bi 0.5 Na 0.5)TiO 3-0.06BaTiO 3 (BNBT), Portland cement, and polyvinylidene fluoride (PVDF). The microstructure, acoustic impedance (Z c), dielectric properties, and influence of poling temperature and electrical poling field on the piezoelectric coefficient (d 33) and the total period of the poling process of composites with 50 vol% BNBT and 1-10 vol% PVDF were investigated. The results indicated that Z c , the dielectric constant, and the dielectric loss of the composites decrease as the PVDF content increases. The d 33 of the composites was found to enhance more clearly when the content of PVDF is more than 2 vol%. The d 33 results of the composites showed an optimum increase of 45% when 5 vol% PVDF was used (under an electrical poling field of 1.5 kV/mm and a poling temperature of 80°C). Moreover, these composites with PVDF were found to exhibit enhanced poling behavior in that the PVDF was able to reduce the total period of the poling process. Interestingly, the piezoelectric voltage coefficient (g 33) of the composite with 5 vol% PVDF content had the highest value of 33.59 mVÁm/N. Therefore, it can be safely concluded that this new kind of PVDF-modified 0-3 connectivity cement-based/lead-free 0.94(Bi 0.5 Na 0.5)TiO 3-0.06BaTiO 3 piezoelectric ceramic composite has the potential to be used in concrete as a sensor for structural health monitoring applications.
An effective approach on Physical and Dielectric properties of PZT-PVDF composites
The 0-3 connected ferroelectric composites made of PZT and PVDF have been examined for its different physical and dielectric properties. The standard methods presented in earlier literatures for the composite preparation have been compared to find an effective method. The distinction in the physical properties like density and porosity of the piezocomposite was studied and their SEM morphological facts are scrutinized. The dielectric constant of PZT-PVDF composite has been predicted by using standard models and the results are compared. Also the relaxation behavior of polymer at higher temperature has been justified. Keywords:PZT-PVDF, dielectric properties, scanning electron microscope, ferroelectric ceramic, ferroelectric polymer.
Investigations on Structural, Mechanical, and Dielectric Properties of PVDF/Ceramic Composites
Journal of Engineering, 2015
Polymer ceramic composites are widely used for embedded capacitor application. In the present work PVDF has been used as a matrix and CCTO and LaCCTO have been used as reinforcement. Extrusion process has been used for the synthesis of composites. X-ray diffraction (XRD) patterns confirm the formation of single phase CCTO, and LaCCTO in its pure as well as composite state. It is found that La doping in CCTO considerably increases the dielectric constant and reduces the dielectric loss. A similar trend is observed in the composites with the increasing content of CCTO and LaCCTO.
j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / m a t c h e m p h y s Preparation, characterization and properties of novel 0–3 ferroelectric composites of Ba 0.95 Ca 0.05 Ti 0.8 Zr 0.2 O 3 –poly(vinylidene fluoride-trifluoroethylene) a b s t r a c t The present work describes the preparation and properties of a novel ceramic–polymer composites using Ba 0.95 Ca 0.05 Ti 0.8 Zr 0.2 O 3 (BCTZ) as a ceramic filler and poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] as a polymer matrix. The BCTZ ceramics were prepared by the conventional solid-state reaction route whereas the BCZT–P(VDF-TrFE) composites with various BCTZ volume fractions were prepared by the combined method of solvent casting and hot pressing. The microstructure of the composites was investigated using scanning electron microscopy and X-ray diffraction. The dependences of the dielectric properties of the composites on BCTZ volume fraction was reported and analyzed in terms of the effective medium theory (EMT). The P–E hysteresis loops of the composites are strongly dependent on the ceramic volume fraction. The composites with higher ceramic volume fractions showed larger remanent polarization and smaller coercive field. The mechanical properties of the composites were investigated. Tensile strength showed enhancement at lower ceramic content and decreased with higher ceramic loading while Young's modulus showed increase with respect to the ceramic loading.
Piezo, ferro and dielectric properties of ceramic- polymer composites of 0-3 connectivity
Ferroelectric PZT-PVDF composites (0–3 connectivity) of specific dimensions were made utilizing a hot press technique. Linear variation in the experimental density of the pellets made from 0.1 to 0.8 PZT volume fraction was observed. The surface morphology of the composite has been micro-graphed using SEM. The variation of the dielectric properties of the composites on PZT volume fractions is reported and analyzed. It is observed that there was an increment in dielectric constant (er) with an increase in temperature and volume fractions. The piezoelectric strain coefficient (d33) increases with an increase in the volume fraction and voltage coefficient (g33) were calculated. Comparisons were made with the Furukawa model to er and d33. The remnant polarization and coercive field were analyzed from the hysteresis plots.