New aspect-ratio effect in three-component composites for piezoelectric sensor, hydrophone and energy-harvesting applications

In this paper the influence of the aspect ratio of ferroelectric ceramic inclusions on the piezoelectric performance and hydrostatic parameters of novel three-component 1-3-type composites based on relaxor-ferroelectric single crystals is studied. Differences in the microgeometry of the ceramic/polymer matrix with 0-3 connectivity and the presence of two piezo-active components with contrasting piezoelectric and mechanical properties lead to a considerable dependence of the piezoelectric performance, hydrostatic response and related parameters of the 1-0-3 composite on the aspect ratio and volume fraction of the aligned ceramic inclusions. The influence of the elastic anisotropy of the ceramic/polymer matrix on composite properties with changes in the aspect ratio and volume fraction of the inclusions is discussed. The piezoelectric performance of the 1-0-3 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystal/modified PbTiO3 ceramic/polymer composite suggests that such a material is of interest for both sensor and energy-harvesting applications due to large values of the piezoelectric coefficient g33∗∼400-550 mV m/N, squared figure of merit d33∗g33∗∼10-10 Pa-1 and related anisotropy factor d33∗g33∗/(d31∗g31∗)∼8-9. Such composites can also be used in hydrophone applications due to their large hydrostatic parameters, e.g., dh∗∼102 pC/N, gh∗∼100-160 mV m/N and dh∗gh∗∼10-11 Pa-1.</p

Domain orientations and piezoelectric properties in novel 2–2-type composites with two single-crystal components

The present paper is concerned with the piezoelectric properties and related parameters of the 2–2-type parallel-connected composites wherein rotations of the main crystallographic axes in ferroelectric single crystal components are analyzed. The composite consists of layers of two types that are regularly arranged along the non-polar axis. The Type I layer is a single domain 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 single crystal (either tetragonal in Composite I or orthorhombic in Composite II). The Type II layer is a Li2B4O7 single crystal/polyethylene medium with 0–3 connectivity. The composite as a whole is characterized by 2–0–2 connectivity. The following parameters of the composite are studied by taking into account the polarization orientation effect in the Type I layer and the microgeometry of the composite in the Type II layer: piezoelectric coefficients (Formula presented.) and (Formula presented.) their hydrostatic analogs (Formula presented.) and (Formula presented.) hydrostatic squared figure of merit (Formula presented.) (Formula presented.) piezoelectric anisotropy factors (Formula presented.) / (Formula presented.) and (Formula presented.) / (Formula presented.) It is shown that large values of the studied piezoelectric coefficients, hydrostatic parameters and anisotropy factors make Composite II more preferable in comparison to Composite I for hydroacoustic, piezoelectric sensor and energy-harvesting applications.</p

Domain orientations and piezoelectric properties in novel 2–2-type composites with two single-crystal components

The present paper is concerned with the piezoelectric properties and related parameters of the 2–2-type parallel-connected composites wherein rotations of the main crystallographic axes in ferroelectric single crystal components are analyzed. The composite consists of layers of two types that are regularly arranged along the non-polar axis. The Type I layer is a single domain 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 single crystal (either tetragonal in Composite I or orthorhombic in Composite II). The Type II layer is a Li2B4O7 single crystal/polyethylene medium with 0–3 connectivity. The composite as a whole is characterized by 2–0–2 connectivity. The following parameters of the composite are studied by taking into account the polarization orientation effect in the Type I layer and the microgeometry of the composite in the Type II layer: piezoelectric coefficients (Formula presented.) and (Formula presented.) their hydrostatic analogs (Formula presented.) and (Formula presented.) hydrostatic squared figure of merit (Formula presented.) (Formula presented.) piezoelectric anisotropy factors (Formula presented.) / (Formula presented.) and (Formula presented.) / (Formula presented.) It is shown that large values of the studied piezoelectric coefficients, hydrostatic parameters and anisotropy factors make Composite II more preferable in comparison to Composite I for hydroacoustic, piezoelectric sensor and energy-harvesting applications.</p

Orientation effects and figures of merit in advanced 2-2-type composites based on [011]-poled domain-engineered single crystals

The paper reports new results that compare the group of performance figures of merit of piezo-active 2-2-type composites based on [011]-poled domain-engineered (1 - x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 single crystals, where the main crystallographic axes in the crystal layers are rotated to tailor effective electromechanical properties and related parameters. Examples of the orientation and volume-fraction dependences of the figures of merit are analysed for the first time for the system of 2-2 single crystal/polymer composites and 2-0-2 single crystal/corundum ceramic/polymer composites at x = 0.0475-0.09. The connections between the piezoelectric coefficients, energy-harvesting figures of merit and modified figures of merit (j = 1, 2 and 3) are highlighted during rotation of the main X and Y crystallographic axes around the Z axis of the crystal layers. A similar orientation behaviour of, and and their large anisotropy are studied at specific volume fractions of the single-crystal component and for a variety of microgeometric architectures of a corundum ceramic/polymer layer with 0-3 connectivity. Maxima of the longitudinal parameters, and at x = 0.0475-0.09 and constant volume fraction of the single-crystal component of the 2-2-type composites are observed in a relatively narrow orientation range. A new performance diagram is built to show regions of a large anisotropy of and in a 2-0-2 composite and, as a result of the large piezoelectric coefficients and figures of merit, the composites show significant potential in the field of piezoelectric energy-harvesting and sensor applications. This journal is </p

Piezoelectric sensitivity and hydrostatic response of novel lead-free 2–0–2 composites with two single-crystal components

This paper reports the piezoelectric performance and important related hydrostatic parameters of 2–0–2 composites based on lead-free ferroelectric and piezoelectric single crystals with 4mm symmetry. We demonstrate that ferroelectric domain-engineered alkali niobate-tantalate based single crystals provide large values of the piezoelectric coefficients g3j ∗ and related parameters when used in a 2–0–2 composite system with a relatively wide range of volume fractions of single-crystal components. An ‘aspect-ratio effect’ as a result of the presence of inclusions of a piezoelectric Li2B4O7 single crystal in a polymer medium is studied for the first time for a case where the elastic compliance s12 in the single crystal/polymer layer of the composite passes through zero. It is observed that changes in the aspect ratio and volume fraction of the Li2B4O7 inclusions influence the hydrostatic piezoelectric coefficient gh ∗, squared figure of merit dh ∗gh ∗ and electromechanical coupling factor kh ∗ of the composite, and large values of gh ∗∼102 mV·m/N, dh ∗gh ∗∼ (10−11–10−10) Pa−1 and kh ∗≈ 0.6–0.7 are achieved. A link between max kh ∗ and a change in sgns12 is first described for the 2–2-type composite, and a comparison of the hydrostatic parameters of the novel and related composites is made. The present results show the potential of lead-free 2–0–2 composites that are suitable for piezoelectric sensor, energy-harvesting and hydroacoustic applications.</p

Relationships between piezoelectric and energy-harvesting characteristics of 1–2–2 composites based on domain-engineered single crystals

The paper reports on the piezoelectric performance, electromechanical coupling and related energy-harvesting figures of merit of three forms of 1–2–2 composites based on domain-engineered single crystals. The effect of the single-crystal piezoelectric properties and elastic properties of the laminar polymer matrix on the appropriate figures of merit of the composite is studied. The main active components of the studied composites are [0 0 1]-poled perovskite-type single crystals with chemical compositions: 0.92Pb(Zn1/3Nb2/3)O3–0.08PbTiO3, 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 and [Li x (K1−y Na y)1−x ](Nb1−z Ta z)O3: Mn, where x = 0.06, y = 0.1–0.3, z = 0.07–0.17, and the level of Mn doping is 0.25 mol. %. Examples of non-monotonic volume-fraction dependences of the piezoelectric properties, figures of merit and anisotropy factors are analysed. New diagrams are first built to demonstrate the volume-fraction regions where a large anisotropy of the piezoelectric coefficients d 3j * and electromechanical coupling factors k 3j * is achieved, and where energy-harvesting figures of merit of the composite are at least five times larger than analogous parameters of single-crystal components. The studied 1–2–2 composites are of interest as anisotropic materials with high piezoelectric sensitivity and large figures of merit which are important for sensor, energy-harvesting and related applications.</p

Electromechanical Coupling Factors of Novel 0-3-0 Composites Based on PMN-xPT Single Crystals

This paper is devoted to the problem of the electromechanical coupling of advanced Single crystals (SCs) of relaxor-ferroelectric solid solutions of with perovskite-type structure are of interest as highly effective components of advanced piezo-active composites. Electromechanical coupling is one of the main characteristics of any piezoelectric media, including composites with the piezo-active components. Recent results on the laminar [1, 2], matrix cellular [3] and fibrous [4] composites based on PMN-0.33PT SCs demonstrate the key role of the piezoelectric coefficients d ij of SC in achieving considerable electromechanical coupling in these composites. Particular features of the behaviour of the electromechanical coupling factors (ECFs) in the 0-3 PMN-xPT SC/ polymer composites were discussed in work The determination of the effective electromechanical properties of the 0-3-0 composit

New aspect-ratio effect in three-component composites for piezoelectric sensor, hydrophone and energy-harvesting applications

In this paper the influence of the aspect ratio of ferroelectric ceramic inclusions on the piezoelectric performance and hydrostatic parameters of novel three-component 1-3-type composites based on relaxor-ferroelectric single crystals is studied. Differences in the microgeometry of the ceramic/polymer matrix with 0-3 connectivity and the presence of two piezo-active components with contrasting piezoelectric and mechanical properties lead to a considerable dependence of the piezoelectric performance, hydrostatic response and related parameters of the 1-0-3 composite on the aspect ratio and volume fraction of the aligned ceramic inclusions. The influence of the elastic anisotropy of the ceramic/polymer matrix on composite properties with changes in the aspect ratio and volume fraction of the inclusions is discussed. The piezoelectric performance of the 1-0-3 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystal/modified PbTiO3 ceramic/polymer composite suggests that such a material is of interest for both sensor and energy-harvesting applications due to large values of the piezoelectric coefficient g33∗∼400-550 mV m/N, squared figure of merit d33∗g33∗∼10-10 Pa-1 and related anisotropy factor d33∗g33∗/(d31∗g31∗)∼8-9. Such composites can also be used in hydrophone applications due to their large hydrostatic parameters, e.g., dh∗∼102 pC/N, gh∗∼100-160 mV m/N and dh∗gh∗∼10-11 Pa-1.</p