DEVELOPMENT OF HIGH POWER TEXTURED PIEZOELECTRIC CERAMICS WITH ULTRAHIGH ELECTROMECHANICAL PROPERTIES FOR LARGE DRIVING FIELD APPLICATIONS
20230145627 · 2023-05-11
Inventors
- Haoyang Leng (State College, PA, US)
- Yongke Yan (Port Matilda, PA, US)
- Shashank Priya (State College, PA, US)
Cpc classification
C04B2235/3284
CHEMISTRY; METALLURGY
C04B2235/3281
CHEMISTRY; METALLURGY
C04B2235/786
CHEMISTRY; METALLURGY
C04B2235/3206
CHEMISTRY; METALLURGY
C04B2235/6587
CHEMISTRY; METALLURGY
C04B2235/3215
CHEMISTRY; METALLURGY
C04B2235/5436
CHEMISTRY; METALLURGY
C04B2235/3255
CHEMISTRY; METALLURGY
International classification
Abstract
Embodiments relate to a piezoelectric ceramic and methods of making the same that is suitable for use as a high-power piezoelectric ceramic, and in particular a piezoelectric ceramic that exhibits both good hard properties and good soft properties. Embodiments involve generating the piezoelectric ceramic via the combination of chemical modification/doping and/or a texturing method so that the piezoelectric material exhibits a large figure of merit, as well as other hard and soft properties. The chemical modification involves Cu and Mn doping a piezoelectric material composition having a relaxor-lead titanate based ferroelectric structure. The texturing involves templated grain growth (TGG) texturing using a BaTiO.sub.3 (BT) template.
Claims
1. A piezoelectric composition, comprising: 0.24 Pb(In.sub.1/2Nb.sub.1/2)O.sub.3-0.42Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3-0.34PbTiO.sub.3 (PIN-PMN-PT) doped with MnO.sub.2 and CuO; wherein >0.0 wt % CuO<=0.5 wt % CuO; and wherein MnO.sub.2 is 2 mol %.
2. The piezoelectric composition of claim 1, wherein a d.sub.33=363 pC/N, Q.sub.m=2800, E.sub.c=10 KV/cm and Q.sub.m.Math.d.sub.33.Math.E.sub.c=1 CV/Nm.
3. The piezoelectric composition of claim 1, wherein: the PIN-PMN-PT includes 0.0 wt % CuO and 2 mol % MnO.sub.2, wherein d.sub.33=370 pC/N, Q.sub.m=1693, E.sub.c=9.33 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.584; the PIN-PMN-PT includes 0.125 wt % CuO and 2 mol % MnO.sub.2, wherein d.sub.33=363 pC/N, Q.sub.m=2800, E.sub.c=10.1 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=1.03; the PIN-PMN-PT includes 0.25 wt % CuO and 2 mol % MnO.sub.2, wherein d.sub.33=374 pC/N, Q.sub.m=2096, E.sub.c=9.81 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.769; or the PIN-PMN-PT includes 0.5 wt % CuO and 2 mol % MnO.sub.2, wherein d.sub.33=372 pC/N, Q.sub.m=1921, E.sub.c=10.1 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.726.
4. A piezoelectric composition, comprising: 0.24 Pb(In.sub.1/2N.sub.1/2)O.sub.3-0.42Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3-0.34PbTiO.sub.3 (PIN-PMN-PT) doped with MnO.sub.2; wherein MnO.sub.2 is 2 mol %; and wherein the composition is textured via a templated grain growth (TGG) method using a BaTiO.sub.3 template.
5. The piezoelectric composition of claim 4, wherein the BaTiO.sub.3 content is >0.0 vol. %<=5 vol. %.
6. The piezoelectric composition of claim 4, wherein the PIN-PMN-PT is doped with CuO.
7. The piezoelectric composition of claim 6, wherein the composition has >0.0 wt % CuO<=0.5 wt % CuO.
8. The piezoelectric composition of claim 6, wherein the PIN-PMN-PT includes 0.25 wt % CuO and 2 mol % MnO.sub.2, wherein d.sub.33>710 pC/N, k.sub.31=0.52, and Q.sub.m≈950.
9. The piezoelectric composition of claim 4, wherein: the PIN-PMN-PT includes 1 vol. % BaTiO.sub.3, wherein d.sub.33=457 pC/N, Q.sub.m=1249, and T.sub.c=207° C.; the PIN-PMN-PT includes 2 vol. % BaTiO.sub.3, wherein d.sub.33=517 pC/N, Q.sub.m=1148, and T.sub.c=205° C.; the PIN-PMN-PT includes 3 vol. % BaTiO.sub.3, wherein d.sub.33=529 pC/N, Q.sub.m=1023, and T.sub.c=205° C.; or the PIN-PMN-PT includes 5 vol. % BaTiO.sub.3, wherein d.sub.33=475 pC/N, Q.sub.m=770, and T.sub.c=199° C.
10. A method of making a high-powered piezoelectric composition, the method comprising: doping 0.24 Pb(In.sub.1/2Nb.sub.1/2)O.sub.3-0.42Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3-0.34PbTiO.sub.3 (PIN-PMN-PT) with MnO.sub.2 and CuO.
11. The method of claim 10, further comprising: texturing the Cu—Mn-doped PIN-PMN-PT via a templated grain growth method (TGG).
12. The method of claim 11, wherein the TGG involves use of a BaTiO.sub.3 template.
13. The method of claim 11, further comprising increasing the tetragonality degree PIN-PMN-PT via TGG.
14. The method of claim 12, wherein the BaTiO.sub.3 content is >0.0 vol. %<=5 vol. %.
15. The method of claim 10, wherein: MnO.sub.2 is 2 mol %; and >0.0 wt % CuO<=0.5 wt % CuO.
16-20. (canceled)
21. A piezoelectric ceramic composition, represented as x Pb(X.sub.1/2Nb.sub.1/2)O.sub.3-y Pb(Y.sub.1/3Nb.sub.2/3)O.sub.3-(1−x−y) PbTiO.sub.3 (PIN-PMN-PT), wherein x=0.20-0.27 and y=0.40-0.45; X=In, Sc, Yb, Fe; and Y=Mg, Zn, Ni; doped with MnO.sub.2 (0.0-2.5 mol %), CuO (0.0-0.5 wt %).
22. The piezoelectric ceramic composition of claim 21, wherein X is In and Y is Mg.
23. The piezoelectric ceramic composition of claim 22, wherein the composition is modified using a 0.0-5 vol % BaTiO.sub.3 template.
24. The piezoelectric ceramic composition of claim 21, wherein the composition is modified using a 0.0-5 vol % BaTiO.sub.3 template.
25. The piezoelectric ceramic composition of claim 24, wherein the composition is formed to exhibit a Lotgering factor from 0 to 100%.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0028] The above and other objects, aspects, features, advantages and possible applications of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings. It should be understood that like reference numbers used in the drawings may identify like components.
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DETAILED DESCRIPTION OF THE INVENTION
[0071] The following description is of an embodiment presently contemplated for carrying out the present invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles and features of the present invention. The scope of the present invention should be determined with reference to the claims.
[0072] Embodiments disclosed herein can include a material that can be configured to have a piezoelectric, a dielectric, and/or an electromechanical property. In some embodiments, the material can be included in a device or other type of apparatus. Some devices can include a plurality of materials. For instance, an exemplary apparatus can be configured as a piezoelectric system or piezoelectric device having at least one embodiment of the material. In some embodiments, the device can be a piezoelectric sensor, a piezoelectric transducer, a piezoelectric generator, a piezoelectric actuator, etc. Some embodiments of the apparatus can be configured for generating a material for piezoelectric devices that may be suitable for high performance electromechanical applications.
[0073] Embodiments of the material may include a ceramic. Embodiments of the material may be configured to include a perovskite crystalline structure. A perovskite crystalline structure can include a general chemical formula of ABX.sub.3, where A.sup.2+ and B.sup.4+ may be cations and X.sup.2− may be oxygen. An exemplary perovskite ceramic can be lead titanate (PbTiO.sub.3), for example. The lattice structure of a perovskite material at room temperature can exhibit phases that are cubic, orthorhombic, tetragonal, monoclinic, rhombohedral, etc. Mixed phases can also exist at the same time and this is advantageous in achieving high soft properties. The oxygen may be located at the face centers of the lattice. The size and/or valence of the A and/or B ions can be changed or controlled to generate distortions and/or introduce instability in the crystalline structure. Some embodiments of the material can include a ferroelectric property. For example, the material can exhibit a polarization that may be modifiable due to an application of an electric filed (E-field).
[0074] Some embodiments of the material can include a binary system or a binary mixture of substances. Some embodiments of a material can include a ternary system or a ternary mixture of substances. Some embodiments of the material can be configured as a binary and/or ternary system. Some embodiments of the material may be configured to include a morphotropic phase boundary (MPB). Some embodiments of the material may be configured to include mixed rhombohedral and/or tetragonal ferroelectric phases. Embodiments of a piezoelectric device may include any one and/or combination of the materials and/or systems described herein.
[0075] Some embodiments of the material may be configured to include a relaxor-based ferroelectric structure. An example can be a relaxor-lead titanate based ferroelectric structure, which may have a general formula of Pb(M.sub.I,M.sub.II)O.sub.3—PbTiO.sub.3. Pb(M.sub.I,M.sub.II)O.sub.3 may be referred to as a relaxor end member. Pb can be referred to as A-site. (M.sub.I,M.sub.II) and/or Ti can be referred to as B-sites. The M.sub.I may be a low valance cation. The M.sub.II may be a high valance cation.
The (M.sub.I,M.sub.II) portion may generate a relaxor component. Relaxor components can include polarized nanoregions (PNRs). PNRs can be formed by causing a nanoscale local region to have a dominant structure with spontaneous polarizations different from a nearby matrix of the material. The spontaneous polarization regions may be with a range from several nanometers to several tens of nanometers. Exemplary materials with PNRs may include lead lanthanum zirconate titanate (PLZT), lead magnesium niobate (PMN), lead zinc niobate (PZN), PMN-lead titanate (PbTiO.sub.3) solid solution, lead barium metaniobate (PBN), Na.sub.1/2Bi.sub.1/2O.sub.3 (NBT), etc. Exemplary relaxor-based ferroelectric materials with perovskite structures can include PMN, PMN-PT, etc.
[0076] An aspect of the method can include use of chemical modifications and/or texturing. Texturing may be done to generate a piezoelectric ceramic with non-randomly orientated grains. More particularly, texturing may be done to increase the tetragonality degree of the piezoelectric ceramic. The chemical modifications may be done to increase vibration velocity (v∝Q.sub.m.Math.d.Math.E.sub.c) of the ceramic. Any one or combination of the embodiments chemical modifications and texturing can be used to generate a piezoelectric ceramic with high strain coefficient d, high electromechanical coupling coefficient k, high mechanical quality factor (Q.sub.m), and/or high coercive field (E.sub.u), thereby leading to high vibration velocity (v∝Q.sub.m.Math.d.Math.E.sub.c) and large figure of merit (Q.sub.m.Math.d.sub.33.Math.E.sub.c). For instance, embodiments of the chemical modified piezoelectric ceramic can exhibit d.sub.33=363 pC/N, Q.sub.m=2800, E.sub.c=10.1 KV/cm and Q.sub.m.Math.d.sub.33.Math.E.sub.c around 1 CV/Nm. Embodiments of the textured piezoelectric ceramic can exhibit d.sub.33>710 pC/N, k.sub.31=0.52, and Q.sub.m≈950.
[0077] Referring to
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Chemical Modification/Doping
[0080] An embodiment involves adding Cu to a Mn-doped piezoelectric ceramic.
[0081] As noted herein, it is desired to have high strain coefficient d, high electromechanical coupling coefficient k, high mechanical quality factor (Q.sub.m), and high coercive field (E.sub.c) to give a high vibration velocity (v∝Q.sub.m.Math.d.Math.E.sub.c) and large figure of merit Q.sub.m.Math.d.sub.33.Math.E.sub.c. Embodiments of the piezoelectric ceramic include a 0.24 Pb(In.sub.1/2Nb.sub.1/2)O.sub.3-0.42Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3-0.34PbTiO.sub.3 (“PIN-PMN-PT”) that is Mn-doped and modified via the addition of Cu. Other example formulations include—Pb(Yb.sub.1/2Nb.sub.1/2)O.sub.3—Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3—PbTiO.sub.3, Pb(Sc.sub.1/2Nb.sub.1/2)O.sub.3—Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3—PbTiO.sub.3, Pb(Zn.sub.1/3Nb.sub.2/3)O.sub.3—Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3—PbTiO.sub.3, Pb(Fe.sub.1/2Nb.sub.1/2)O.sub.3—Pb(Mn.sub.1/3Nb.sub.2/3)O.sub.3—PbTiO.sub.3, etc. For example, the piezoelectric ceramic can be 0.125 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT. The 0.125 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT exhibits a figure of merit (Q.sub.m.Math.d.sub.33.Math.E.sub.c) of at least 1 CV/Nm, which is over 2 times higher than the state-of-art commercial piezoelectric ceramics including PZT4 and PZT8 (0.21 and 0.43 CV/Nm, respectively). The 0.125 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT also has d.sub.33=363 pC/N, Q.sub.m=2800, E.sub.c=10.1 KV/cm.
[0082] The Cu—Mn doped PIN-PMN-PT with 0.125 wt % CuO is exemplary. The wt % of CuO can range from 0.0 wt % to 0.5 wt %. Table 1 shows a 0.0 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT having d.sub.33=370 pC/N, Q.sub.m=1693, E.sub.c=9.33 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.584. A 0.125 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT has d.sub.33=363 pC/N, Q.sub.m=2800, E.sub.c=10.1 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=1.03. A 0.25 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT has d.sub.33=374 pC/N, Q.sub.m=2096, E.sub.c=9.81 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.769. A 0.5 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT has d.sub.33=372 pC/N, Q.sub.m=1921, E.sub.c=10.1 KV/cm, and a Q.sub.m.Math.d.sub.33.Math.E.sub.c=0.726.
Exemplary Cu—Mn Doped PIN-PMN-PT Ceramic
[0083] Exemplary samples of a Cu—Mn doped PIN-PMN-PT were fabricated to ascertain the hard and soft properties of such a piezoelectric ceramic. The fabrication of the samples involved generating a matrix powder, the matrix powder including a composition of 2 mol % MnO.sub.2 doped PIN-PMN-PT synthesized by a two-step columbite precursor method. Raw materials of In.sub.2O.sub.3 and Nb.sub.2O.sub.5 were used to prepare InNb.sub.2O.sub.4 precursor at 1100° C. for 7 h. Stoichiometric amounts of PbO, InNb.sub.2O.sub.4, MgNb.sub.2O.sub.6, TiO.sub.2, and MnO.sub.2 were mixed in ethanol for 24 h. The dried mixtures were calcined at 850° C. for 4 h. Different samples were produced, each having different amounts of CuO added into the Mn doped PIN-PMN-PT calcined powder. The calcined powders were balled milled in ethanol for 48 h to decrease the particle sizes. The balled milled powders were pressed into pellets with 12 mm in diameter. The pellets were embedded in calcined Mn-doped PIN-PMN-PT powders containing 1.5 wt % excess PbO within a closed crucible and sintered at 1150-1220° C. for 6 h in air.
[0084] The crystal phases of the sintered pellets were determined using X-ray diffraction (XRD). Microstructures were evaluated using scanning electron microscopy (SEM). For electrical measurements, the sample surfaces were polished and coated with silver paste. All the samples were poled at 40 kV/cm for 30 min at 140° C. After aging for 48 h, the piezoelectric coefficient d.sub.33 was measured by using a d.sub.33 meter. Polarization vs. electric field (P-E) hysteresis loop was measured using a modified Sawyer-Tower circuit.
[0085] The mechanical coupling coefficient (k) and mechanical quality factor (Q.sub.m) were measured by resonance and anti-resonance technique using impedance analyzer.
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[0088] Table 1 lists the dielectric and piezoelectric properties for Mn doped PIN-PMN-PT ceramics with different CuO contents. Particularly, the Mn doped PIN-PMN-PT sample with 0.125 wt % CuO exhibited a giant figure of merit of Q.sub.m.Math.d.sub.33.Math.E.sub.c around 1 CV/Nm, which is significantly higher than most commercial piezoelectric ceramics including PZT4 and PZT8 (0.21 and 0.43 CV/Nm, respectively).
TABLE-US-00001 TABLE 1 Dielectric and piezoelectric properties for Mn doped PIN-PMN-PT ceramics with different CuO contents. E.sub.c tan δ d.sub.33 d.sub.33 × E.sub.c × Q.sub.m Specimen (KV/cm) ε.sub.33.sup.T/ε.sub.o (%) (pC/N) k.sub.T k.sub.P Q.sub.m (CV/Nm) 2 mol. % Mn doped 9.33 1447 0.47 370 0.57 0.56 1693 0.584 PIN-PMN-PT 0.125 wt % CuO-2 mol. % 10.1 1452 0.54 363 0.57 0.54 2800 1.03 Mn doped PIN-PMN-PT 0.25 wt % CuO-2 mol. % 9.81 1460 0.57 374 0.57 0.53 2096 0.769 Mn doped PIN-PMN-PT 0.5 wt % CuO-2 mol. % 10.1 1409 0.97 372 0.57 0.54 1921 0.726 Mn doped PIN-PMN-PT
[0089] In summary, CuO dopant can enhance both sintering ability and piezoelectric properties of Mn doped PIN-PMN-PT ceramics. Particularly, the Mn doped PIN-PMN-PT sample with 0.125 wt % CuO exhibited good piezoelectric properties of d.sub.33=363 pC/N, Q.sub.m=2800, Ec=10.1 KV/cm, along with giant figure of merit of Q.sub.m.Math.d.sub.33.Math.E.sub.c around 1 CV/Nm, which is much superior than most commercial piezoelectric ceramics.
Texturing
[0090] Texturing is a process that provides grain orientation along specific crystallographic direction of a piezoelectric ceramic. This can be done to align some or all of the grains. Texturing is a known means to develop high performance piezoelectric ceramics from non-single crystal ceramics as an alternative to single crystal piezoelectric ceramics—e.g., single crystal piezoelectric ceramics tend to be expensive, and thus texturing of non-single crystal ceramics can be a suitable alternative. Embodiments of the texturing method disclosed herein involve a templated grain growth (TGG) method that uses a BaTiO.sub.3 (“BT”) template. The texturing method can be referred to as a BT-TGG.
[0091] In a randomly oriented ceramic, both high Q.sub.m and high d.sub.33 are not achievable because any increase in Q.sub.m and E.sub.c via domain pinning will result in the degradation of d.sub.33 and k. Yet, embodiments of the PIN-PMN-PT can be textured via the BT-TGG method to increase the piezoelectric response of the ceramic—i.e., BT-TGG texturing can improve both the strain coefficient, d, and electromechanical coupling coefficient, k. As will be explained herein, the BT-TGG method increases the texturing degree of the PIN-PMN-PT, leading to the BT-TGG textured PIN-PMN-PT exhibiting ultrahigh piezoelectric properties with d.sub.33>710 pC/N, k.sub.31=0.52, and which are superior than most reported and commercial piezoelectric ceramics.
[0092] Relaxor-based PIN-PMN-PT ternary ferroelectrics have been widely investigated due to their superior piezoelectric properties including high phase transition temperatures (T.sub.r-t and T.sub.c) and high coercive field (E.sub.c) in comparison with Pb(Mg.sub.1/3Nb.sub.2/3)O.sub.3—PbTiO.sub.3 (PMN-PT) binary ferroelectrics. Mn-doping can be used to generate the hard properties of piezoelectric ceramics, where Mn.sup.3+ will substitute B-site in perovskite structure of piezoelectric materials creating oxygen vacancies and the oxygen vacancies will diffuse to the domain boundary region and pin the domain wall motion resulting in hard effect (high Q.sub.m and low tan δ).
[0093] Embodiments disclosed herein involve texturing 2 mol. % MnO.sub.2 doped PIN-PMN-PT ceramics using a BT-TGG method. The effects of template content on <001> texturing degree, microstructures, and dielectric and piezoelectric properties of textured Mn-doped PIN-PMN-PT ceramics were investigated. In addition, the CuO dopant was added to promote the texturing development of Mn doped PIN-PMN-PT ceramics. It was found that the textured ceramics can exhibit excellent soft and hard combinatory properties in comparison with random counterparts, demonstrating that the texturing is an effective method to improve the piezoelectric response of piezoelectric ceramics.
Exemplary BT-TGG Textured PIN-PMN-PT Ceramic
[0094] Exemplary samples of BT-TGG textured PIN-PMN-PT were fabricated to ascertain the hard and soft properties of such piezoelectric ceramic.
[0095] The first set of samples were Mn-doped PIN-PMN-PT ceramics textured via BT-TGG. The BT-TGG textured Mn-doped PIN-PMN-PT exhibited enhanced piezoelectric coefficient d.sub.33 and electromechanical coupling factor k.sub.31 in comparison with a random counterpart. The effects of BT template content on piezoelectric properties of the PIN-PMN-PT ceramic was investigated. It was found that the addition of BaTiO.sub.3 templates can increase the tetragonality degree of the textured ceramics, resulting in improved coercive field E.sub.c in comparison with random counterpart. In addition, the high BT content (>3 vol. %) can slightly lower the d.sub.33 of the textured PIN-PMN-PT ceramic, indicating that the enhancement of piezoelectric coefficient brought by high texturing degree (around 95%) will be reduced by the phase structure evolution to a tetragonal phase region. Two textured ceramics (one with 2 vol. % and one with 3 vol. % BT template—referred to as Textured-2BT and Textured 3BT) are shown to exhibit a high d.sub.33 (>510 pC/N) and high Q.sub.m (>1000).
[0096] The second set of samples were CuO modified Mn-doped PIN-PMN-PT ceramics textured via BT-TGG. The CuO dopant was found to promote the texturing development of the Mn doped PIN-PMN-PT. Particularly, CuO-doped textured-1BT ceramic (1BT meaning 1 vol. % BT template) can exhibit high texturing degree over 94% with ultrahigh piezoelectric properties of d.sub.33>710 pC/N, k.sub.31=0.52, and Q.sub.m≈950, which is superior than most reported and commercial piezoelectric ceramics. For instance, a BT-TGG 0.25 wt % CuO and 2 mol % MnO.sub.2 doped PIN-PMN-PT exhibits a high Q.sub.m.Math.d. (e.g., texture degree over 94%), and ultrahigh piezoelectric properties of d.sub.33>710 pC/N, k.sub.31=0.52, and Q.sub.m≈950.
[0097] The fabrication of the samples involved generating a matrix powder, the matrix powder including a composition of 2 mol. % MnO.sub.2 doped PIN-PMN-PT synthesized by a two-step columbite precursor method. Raw materials of In.sub.2O.sub.3 and Nb.sub.2O.sub.5 were used to prepare InNb.sub.2O.sub.4 precursor at 1100° C. for 7 h. Stoichiometric amounts of PbO, InNb.sub.2O.sub.4, MgNb.sub.2O.sub.6, TiO.sub.2, and MnO.sub.2 were mixed in ethanol for 24 h. The dried mixtures were calcined at 850° C. for 4 h. The calcined powders were balled milled in ethanol for 72 h to decrease the particle size.
[0098] BaTiO.sub.3 (BT) templates were prepared by two-step topochemical microcrystal conversion (TMC) method. The 2 mol. % Mn-doped PIN-PMN-PT ceramics were textured by the templated grain growth (TGG) using x vol. % BT templates (x=1, 2, 3, 5). The samples are abbreviated as textured-xBT hereafter. The matrix powders, templates, organic binder, and toluene solvent were mixed to prepare the slurries for tape casting. The dried tapes were cut, stacked, and laminated to fabricate green samples. After binder burnout at 550° C. and cold-isostatic pressing at 200 MPa, the samples were then embedded in calcined Mn-doped PIN-PMN-PT powders containing 1.5 wt % excess PbO within a closed crucible and sintered at 1220° C. for 6 h in air.
[0099] The crystal phases of the textured samples were determined using X-ray diffraction. The degree of pseudocubic <001> texture was determined by Logtering factor method. Microstructures were evaluated using SEM in combination with energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD). For electrical measurements, the sample surfaces were polished and coated with silver paste. All the samples were poled at 40 kV/cm for 30 min at 140° C. After aging for 48 h, the piezoelectric coefficient d.sub.33 was measured by using a d.sub.33 meter. Temperature-dependent dielectric permittivity (ε.sub.r) and loss tangent (tan δ) were measured with a multifrequency LCR meter. Temperature-dependent dielectric permittivity (ε.sub.r) and loss tangent (tan δ) were used to further elucidate the phase structure. Polarization vs. electric field (P-E) hysteresis loop was measured using a modified Sawyer-Tower circuit. The mechanical coupling coefficient (k) and mechanical quality factor (Q.sub.m) were measured by resonance and anti-resonance technique using impedance analyzer.
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[0103] The EBSD inverse pole figure maps (see
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[0105] EDS mapping of textured ceramic are shown in
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[0109] Table 2 shows the dielectric and piezoelectric properties for both random, textured, and reported (conventional) piezoelectric ceramics. In the Table, x BT refers to x vol. % BT templates (e.g., 0BT=vol. 0% BT, 1BT=vol. 1% BT, 2BT=vol. 2% BT, 3BT=vol. 3% BT, and 5BT=vol. 5% BT). Mn doped textured PMN-PT ceramic exhibits good piezoelectric properties with low T.sub.c (d.sub.33=517 pC/N, Q.sub.m=714, T.sub.c=130° C.). In comparison, the BT textured Mn doped PIN-PMN-PT ceramics (e.g., 1-BT, 2-BT, 3-BT, and 4-BT) showed improved piezoelectric properties with high T.sub.c. Particularly, textured-2BT sample exhibited an excellent combined soft and hard piezoelectric properties of d.sub.33=517 pC/N, Q.sub.m=1148, along with high T.sub.c around 205° C.
TABLE-US-00002 TABLE 2 Dielectric and piezoelectric properties for both random and textured piezoelectric ceramics, compared to reported (conventional) textured Mn doped PMN-PT ceramic CuO-doping effect on BT-TGG Method F.sub.001 T.sub.c E.sub.c tan δ d.sub.33 d.sub.31 Specimen (%) (° C.) (KV/cm) ε.sub.33.sup.T/ε.sub.o (%) (pC/N) (pC/N) k.sub.31 Q.sub.m 2 mol. % Mn doped 0 213 9.37 1351 0.58 370 122 0.34 1693 PIN-PMN-PT-0BT 2 mol. % Mn doped 80 207 10.01 1422 0.47 457 155 0.40 1249 PIN-PMN-PT-1BT 2 mol. % Mn doped 84 205 10.04 1514 0.49 517 169 0.42 1148 PIN-PMN-PT-2BT 2 mol. % Mn doped 91.4 205 10.01 1520 0.49 529 175 0.42 1023 PIN-PMN-PT-3BT 2 mol. % Mn doped 49 130 — — 0.5 517 — 0.44 714 PMN-25P-7 vol. % NBT-0.6PT[19] 2 mol. % Mn doped 95 199 11.4 1432 0.52 475 157 0.40 770 PZT-PMN-PZN-5BT
[0110] A high texturing degree is usually required to achieve single crystal-like piezoelectric response for textured ceramics. Based on the results of a BT-TGG textured Mn-doped PIN-PMN-PT samples, texturing degree over 90% can be achieved using high content of BT template (>3 vol. %). However, the addition of high content of BT template can shift the phase structure of piezoelectric ceramic to tetragonal side due to the high tetragonality of BT template. It is known that the piezoelectric response of PIN-PMN-PT is phase-sensitive, and the highest piezoelectric response can be obtained at the composition close to MPB region similar to PZT. Thus, both texturing degree and phase structure should be considered in order to achieve a giant piezoelectric response of textured ceramic. The textured ceramic with high texturing degree and less heterogenous BT template can be used to meet such requirements. CuO dopant can promote the densification of piezoelectric ceramic at reduced temperature. In addition, the Cu-ion can substitute the AB sites of the perovskite structure to enhance the piezoelectric properties of the ceramic. Thus, integrating CuO-doping, chemical modification (Mn-doping), and BT-TGG texturing can be used to develop a high-power textured PIN-PMN-PT ceramic with ultrahigh piezoelectric response.
Exemplary CuO Doped BT-TGG Textured PIN-PMN-PT Ceramic
[0111] Exemplary samples of CuO doped BT-TGG textured PIN-PMN-PT were fabricated to ascertain the hard and soft properties of such piezoelectric ceramic. Samples of a 2 mol. % Mn-doped PIN-PMN-PT ceramic doped with 0.125 and 0.25 wt. % CuO were textured by the BT-TGG texturing method using x vol. % BT templates (x=0.5, 1, 2). The samples are abbreviated as textured-xBT hereafter. Matrix powders, templates, organic binder, and toluene solvent were mixed to prepare the slurries for tape casting. The dried tapes were cut, stacked, and laminated to fabricate green samples. After binder burnout at 550° C. and cold-isostatic pressing at 200 MPa, the samples were then embedded in calcined Mn-doped PIN-PMN-PT powders containing 1.5 wt % excess PbO within a closed crucible and sintered at 1200-1220° C. for 6 h in air.
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[0120] Table 3 lists the dielectric and piezoelectric properties of CuO-doped textured ceramics. Particularly, the CuO-doped textured-1BT ceramic exhibited excellent combinatory soft and hard piezoelectric properties of d.sub.33=713 pC/N, k.sub.31=0.52, Q.sub.m=949, and E.sub.c=9.64 KV/cm.
TABLE-US-00003 TABLE 3 Dielectric and piezoelectric properties for textured piezoelectric ceramics with different CuO contents, compared to reported (conventional) textured Mn doped PMN-PZT and PMN-PT ceramics F.sub.001 T.sub.c E.sub.c tan δ d.sub.33 d.sub.31 Specimen (%) (° C.) (KV/cm) ε.sub.33.sup.T/ε.sub.o (%) (pC/N) (pC/N) k.sub.31 Q.sub.m 0.25 wt % CuO-2 mol. % Mn doped 97 205 9.7 1498 0.42 725 247 0.54 716 PIN-PMN-PT-2BT + 1200° C. 6 h 0.25 wt % CuO-2 mol. % Mn doped >90 — 10.5 1437 0.49 652 222 0.51 815 PIN-PMN-PT-2BT + 1220° C. 6 h 0.25 wt % CuO-2 mol. % Mn doped 94.2 205 9.64 1588 0.45 713 240 0.52 949 PIN-PMN-PT-1BT + 1200° C. 6 h 0.25 wt % CuO-2 mol. % Mn doped 64 — 9.94 1483 0.45 465 157 0.40 1542 PIN-PMN-PT-0.5BT + 1200° C. 6 h 0.125 wt % CuO-2 mol. % Mn doped >90 — 9.32 1603 0.41 674 234 0.51 906 PIN-PMN-PT-1BT + 1200° C. 6 h 1 mol. % Mn doped >90 198 — 1723 0.29 680 230 0.52 428 PMN-PZT-5BT[4] 2 mol. % Mn doped 49 130 — — 0.5 517 — 0.44 714 PMN-25PT-7NBT-PT[19]
[0121] In addition, both CuO-doped textured-1BT and 2BT ceramics exhibited much better combined soft and hard piezoelectric properties (d.sub.33, k.sub.31, and Q.sub.m) in comparison with the reported (conventional) textured lead-free and lead-based piezoelectric ceramics, which is shown in
[0122] The test results indicate that high power piezoelectric ceramics can be successfully fabricated using integrated texturing and chemical modification (Mn-doping) methods. In addition, the effect of template content on piezoelectric properties of textured ceramics was investigated. The results show that the BT template content in textured ceramic should not exceed 3 vol. % to achieve an optimized combined soft and hard piezoelectric properties since the high template content (>3 vol. %) can increase the tetragonality degree of textured ceramic, resulting in decreased piezoelectric coefficient. Particularly, the textured Mn-doped PIN-PMN-PT with 2 vol. % BT template exhibited excellent piezoelectric properties of d.sub.33=517 pC/N, Q.sub.m=1148, E.sub.c=10 KV/cm.
[0123] In addition, the CuO dopant was found to promote the texturing development of Mn doped PIN-PMN-PT. Both CuO-doped textured-1BT and 2BT ceramics can exhibit high texturing degree over 94% in comparison with undoped textured-2BT counterpart with 84% texturing degree, indicating that the CuO dopant is an effective additive to enhance the texturing development of Mn-doped PIN-PMN-PT ceramics. Under the assistance of CuO dopant, the BT template content can be reduced to lower the tetragonality of textured ceramic without deteriorating its high texturing degree. Finally, ultrahigh piezoelectric properties with d.sub.33>710 pC/N, k.sub.31=0.52, and were achieved in textured ceramics using integrated CuO-doping, chemical modification (Mn-doping), and texturing method. The developed textured ceramics possess much superior combined soft and hard piezoelectric properties in comparison with both reported and commercial piezoelectric ceramics.
Additional Examples
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[0125] Table 4 shows dielectric and piezoelectric properties for both random and textured MC-doped 0.16PIN-0.51PMN-0.33PT piezoelectric ceramics.
TABLE-US-00004 TABLE 4 Dielectric and piezoelectric properties for both random and textured MC-doped 0.16PIN-0.51PMN-0.33PT piezoelectric ceramics d.sub.33 E.sub.c Specimen ε.sub.33 .sup.T/ε.sub.o (pC/N) Q.sub.m (KV/cm) MC doped 1530 628 610 9.0 0.16PIN-0.51PMN- 0.33PT-5BT Random 1449 378 1069 8.50
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[0127] Table 5 shows dielectric and piezoelectric properties for both random and textured MC-doped 0.28PIN-0.40PMN-0.32PT piezoelectric ceramics.
TABLE-US-00005 TABLE 5 Dielectric and piezoelectric properties for both random and textured MC-doped 0.28PIN-0.40PMN-0.32PT piezoelectric ceramics d.sub.33 E.sub.c Specimen ε.sub.33 .sup.T/ε.sub.o (pC/N) Q.sub.m (KV/cm) MC doped 2070 467 1251 10.6 0.28PIN-0.40PMN- 0.32PT-5BT Random 842 250 1760 9.0
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[0129] Table 6 shows dielectric and piezoelectric properties for both random and textured MC-doped 0.36PIN-0.30PMN-0.34PT piezoelectric ceramics.
TABLE-US-00006 TABLE 6 Dielectric and piezoelectric properties for both random and textured MC-doped 0.36PIN-0.30PMN-0.34PT piezoelectric ceramics d.sub.33 E.sub.c Specimen ε.sub.33 .sup.T/ε.sub.o (pC/N) Q.sub.m (KV/cm) MC doped 1550 441 821 12.4 0.36PIN-0.30PMN- 0.34PT-5BT Random 1449 360 904 10.7
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[0136] It should be understood that the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points. It should also be appreciated that some components, features, and/or configurations may be described in connection with only one particular embodiment, but these same components, features, and/or configurations can be applied or used with many other embodiments and should be considered applicable to the other embodiments, unless stated otherwise or unless such a component, feature, and/or configuration is technically impossible to use with the other embodiment. Thus, the components, features, and/or configurations of the various embodiments can be combined together in any manner and such combinations are expressly contemplated and disclosed by this statement.
[0137] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible considering the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof.
[0138] It should be understood that modifications to the embodiments disclosed herein can be made to meet a particular set of design criteria. Therefore, while certain exemplary embodiments of the composition and methods of using and making the same disclosed herein have been discussed and illustrated, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.