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Comprehensive analysis of Mn:PIN-PMN-PT single crystals for Class IV flextensional transducer
Ceramics International 44 (2018) 2864–2868
Contents lists available at ScienceDirect
Ceramics International journal homepage: www.elsevier.com/locate/ceramint
Comprehensive analysis of Mn:PIN-PMN-PT single crystals for Class IV flextensional transducer ⁎
T
⁎
Rongjing Guoa, Shiyang Lia, , Dawei Ana, Tao Hana, Jing Chena, , Wenwu Caob a b
Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
A R T I C L E I N F O
A B S T R A C T
Keywords: Mn modified single crystal Heat generation High power Flextensional transducer
As a crucial part of flextensional transducer (FT), the piezoelectric stack has an essential influence on the transducer. However, up to date, there are no literatures on considering the loss characteristics of the piezoelectric materials in the design of FT. Manganese-modified PIN-PMN-PT (Mn:PIN-PMN-PT) single crystals have greatly improved Qm values compared with the binary and ternary single crystals. In this paper, Class IV FTs based on Mn:PIN-42%PMN-32%PT and Mn:PIN-47%PMN-29%PT crystals were analyzed comprehensively on the heat losses, as well as transmitting voltage response (TVR), source level (SL), acoustic pressure (AP) and admittance. Compared with PIN-47%PMN-29%PT, PMN-28%PT and PZT4, the Mn:PIN-42%PMN-32%PT FT has a decrease of heat loss by 47.9%, 79.5% and 93.6%, respectively, under the same strain of 5 × 10−5. The results indicated that the Mn:PIN-PMN-PT FT possesses simultaneously the less heat loss and lower resonant frequency, the higher AP, TVR, SL and effective electromechanical coupling coefficient. This research provides a guide for the design of FT and illuminates the immense potential of Mn:PIN-PMN-PT single crystals in making low heat generation, low frequency and high power FT.
1. Introduction The Class IV flextensional transducer (FT), which is a typical low frequency, high power and small size transducer, is widely applied in underwater acoustic projector [1]. Many researchers have focused on the design of the transducer structure. However, in the practical application, transducers usually work under the high driving voltage and vibration amplitude. Internal losses occur inevitably and are converted into heat [2]. High power and long term usage of the transducer will cause accumulation of the heat inside the transducer, which can result in temperature rise of the transducers [3]. Excessive temperature rise will seriously deteriorate the performance and the reliability life of the transducer. In recent years, heat problem has drawn considerable attentions. Roh and Kang simulated the effects of the shell sizes on the temperature of the FT by finite element method [3]. However, the effect of piezoelectric material dissipation for the transducer wasn't considered. As a crucial part that transform electrical energy to mechanical energy, the properties and thermal loss of piezoelectric material have an essential influence on the transducer in high power applications. For the underwater transducers, the features of lower driving frequency, wider frequency band and less power loss are desired. Therefore, it is necessary to consider the loss characteristics of the piezoelectric
⁎
materials, as well as the acoustic parameters in the design of the FT. Over the past decades, relaxor-based single crystals have attracted much attention owing to their ultrahigh piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 0.90). The first generation single crystals, such as Pb(Mg1/3Nb2/ 3)O3-PbTiO3 (PMN-PT), have been used in Tonpilz transducer [4]. Compared with conventional Pb(Zr,Ti)O3 (PZT) piezoelectric ceramics, PMN-PT has been demonstrated to possess improvements of the bandwidth and source level of the transducers [5–11]. However, the binary crystals possess low coercive field Ec (~ 2–3 kV/cm), low mechanical quality factor Qm (~ 190), low rhombohedral-to-tetragonal phase transition temperature (TRT ~ 60–100 °C), restricting their practical applications in the high power transducer. The second generation single crystals, ternary Pb(In1/2Nb1/2)O3-Pb(Mb1/3Nb2/3)O3-PbTiO3 (PINPMN-PT), have higher TC (being on the order of 180–220 °C), and higher coercive field Ec (being on the order of ~ 5 kV/cm) than PMNPT, showing much improvement of temperature stability and electric field stability, while maintaining the competence in piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 0.90) [11]. For high power applications, high Qm value is desired to reduce heat generation. However, PIN-PMN-PT has not improved much in the Qm value (~ 290).
Corresponding authors. E-mail addresses: [email protected] (S. Li), [email protected] (J. Chen).
http://dx.doi.org/10.1016/j.ceramint.2017.11.033 Received 2 October 2017; Received in revised form 30 October 2017; Accepted 6 November 2017 Available online 07 November 2017 0272-8842/ © 2017 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Ceramics International 44 (2018) 2864–2868
R. Guo et al.
Table 2 The sizes of the class IV FT. Parameter (mm)
Parameter (mm)
Semi Minor axis length Shell thickness Piezoelectric stack length
36 8 28.5
Semi major axis length Shell height Piezoelectric stack radius
72 90 8
Mn:PIN-47%PMN-29%PT single crystals, as well as PIN-47%PMN-29% PT, PMN-28%PT and PZT4, are listed and compared in Table 1. MaT T terial parameters ρ , TRT, d33, ε33 , k33, Ec, Qm, tanδ , s33 represent density, rhombohedral-to-tetragonal phase transition temperatures, piezoelectric coefficient relating strain/electric field, dielectric permittivity, coercive field, mechanical quality factor, dielectric loss factor and elastic compliance constant, respectively. In order to calculate conveniently, one eighth of the whole finite element model is set up using commercial finite element software ANSYS. The sizes are shown in Table 2. The models in air and water environment are shown in Fig. 2. In this model, the aluminum material and stainless steel are applied on the cylindrical shell and transition structure, respectively. The piezoelectric materials listed in Table 1 are selected as the drive materials. In addition, fluid-structure coupling load was imposed on the fluid-structure interface (FSI) layer, which represents the interaction between the water and the transducer. Then all the analyses are performed in water environment.
Fig. 1. The whole finite element transducer model in air.
Recently, the third generation crystals, manganese-modified PINPMN-PT (Mn:PIN-PMN-PT) crystals have greatly improved Qm value (~ 810), which is comparable to that of the hard PZT ceramics. Compared with the ternary single crystals, Mn:PIN-PMN-PT has similar piezoelectric properties. Considering of much enhanced Qm value and a moderate increment in the phase transition temperature by the addition of Mn, together with the comparable piezoelectric and electromechanical properties, Mn:PIN-PMN-PT single crystal will be a potential candidate for high power FT. However, up to date, there are no reports in the literature on the effects of Mn:PIN-PMN-PT single crystal on FT by considering simultaneous energy losses and underwater acoustic properties. In this work, comprehensive analysis of a class IV FT based on Mn:PIN-PMN-PT crystals is performed. The effects of PT component for Mn:PIN-PMN-PT crystals (Mn:PIN-42%PMN-32%PT and Mn:PIN-47% PMN-29%PT) on the FTs are discussed. Meanwhile, the properties of the class IV FTs based on Mn:PIN-PMN-PT crystals are investigated and compared with binary PMN-PT crystal, ternary PIN-PMN-PT crystal, and conventional PZT ceramic by considering simultaneously energy losses, admittance, bandwidth, transmitting voltage response (TVR), source level (SL) and acoustic pressure (AP). The intent of this work is to perform a global analysis and illuminate the potential of Mn:PINPMN-PT single crystal in making less energy loss, low frequency and high power FTs.
3. Results and discussions For the underwater transducers, general characterization that includes corresponding admittance spectrum, TVR, SL, AP are investigated to evaluate the performance of transducer. 3.1. The analysis of the admittance The in-water admittance spectra of FTs based on the five materials are simulated and shown in Fig. 3. The peaks with maximum and minimum admittance corresponds to the resonant frequency fr and antiresonant frequency fa of the FTs, respectively. Generally, the resonant frequency is mainly determined by shell shape of the transducer [19]. However, because the shells are the same in all simulations for the five drive materials in this paper, the differences of admittance curves of FTs are mainly caused by its drive materials. The differences of the resonant frequencies of FT based on the five piezoelectric materials can also be observed from Fig. 3. The FTs driven by all four single crystals present lower frequencies than PZT4 PT. Among these crystals, the Mn:PIN-PMN-PT transducers exhibit better low-frequency performances than counterparts. Especially, the Mn:PIN42%PMN-32%PT FT, which possesses the lowest resonance frequency, is 150 Hz and 450 Hz lower than PMN-28%PT and PZT4 FTs, respectively. This demonstrated that the manganese-modified crystal is the most appropriate choice for fabricating low frequency FTs. In addition, the effective electromechanical coupling coefficient (keff), which is a key parameter to evaluate the performance of transducer and represents the energy conversion capacity, can be calculated
2. Model and material constants of the transducer In our works, Class IV FT consists of a pair of cylindrical piezoelectric stack that serve as the active driver and an elliptical shell that serves as an acoustic radiator, just as shown in Fig. 1. Because of the displacement amplification effect provided by elliptic shell based on leverage effect, small extensional displacement produced by piezoelectric stacks is transmitted into large volume displacement on the elliptical shell, which can output the acoustic radiated power. To address the effect and the advantage of Mn:PIN-PMN-PT crystal on the FT, the material properties of Mn:PIN-42%PMN-32%PT,
Table 1 The characteristics comparison of Mn:PIN-PMN-PT, PMN-PT, PIN-PMN-PT single crystals and PZT4 [9,12–18]. Material
Mn:PIN-42%PMN-32%PT Mn:PIN-47%PMN-29%PT PIN-47%PMN-29%PT PMN-28%PT PZT4
ρ
TRT
d33
Ec
Qm,
pC/N
/
kV/cm
%
T s33 10−12 m2/N
tanδ
°C
T ε33 ε0
k33
kg/m2 8100 8173 8122 8095 7500
128 128 125 95 /
1341 855 1285 1182 289
3811 2599 4753 5479 1300
0.92 0.86 0.89 0.91 0.74
11.5 11.5 5.0 2.5 14
810 810 290 190 500
64.96 43.07 49.04 34.30 15.0
0.16 0.16 0.15 0.26 0.3
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%
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Fig. 2. One eighth of the whole finite element transducer model of the Class IV FT: (a) in air environment, (b) in water environment.
3.2. The analysis of energy loss In FTs, the energy loss generally includes the dielectric and mechanical loss, shown as follows [21–23]:
Qgen = Qmec + Qele
(2)
where Qmec and Qele are the mechanical loss and electrical loss, respectively. Because the shell is the same in the analysis of the different piezoelectric stack, the mechanical loss of the shell is regarded as identical under the same shell strain. So, we mainly focus on the effects of the each piezoelectric materials on FTs, the mechanical loss of only the piezoelectric stack is considered as [21–23]:
Qmec =
1 ωT3 S3 VPS 2Qm
(3)
where, T3 and S3 represent stress and strain, respectively; ω is angular frequency and is equal to 2πf ; VPS is the volume of the piezoelectric stack. T3 and S3 are shown as following [24,25]: Fig. 3. The admittance spectra of IV FTs for five kinds of materials.
T3 =
Table 3 Comparison of the electromechanical coupling coefficient (keff) of FTs with different drive materials. Materials
fr(Hz)
fa(Hz)
keff
Mn:PIN-42%PMN-32%PT Mn:PIN-47%PMN-29%PT PIN-47%PMN-29% PMN-28%P PZT4
2550 2650 2650 2750 2950
3200 3150 3200 3350 3250
0.604 0.540 0.560 0.571 0.419
1 S − e33 E3 E 3 S33
S3 = d33 E3
(5)
E3 = V / d
(6)
where V, e33 , E3 and d present the driving voltage, piezoelectric coefficient relating stress/electric field, electric-field magnitude and the thickness of stack piece, respectively. As a part of the energy loss, the dielectric loss can be calculated as [21–23]:
Qele = as follows [20]:
keff =
1 2 T E3 ωε33tanδVPS 2 T ε33
(7)
and tanδ is the dielectric permittivity and dielectric loss where factor, respectively. Because the strain of the piezoelectric stack is proportional to the output displacement of transducer, the strain of the piezoelectric stack is used in the analysis of the energy loss. According to Eqs. (2)–(7), the relationships of the energy loss and strain for all five piezoelectric materials are obtained and shown in Figs. 4–6. These figures exhibit an exponential growth of the losses with the increase of strain. For three types of the losses, the transducer with Mn:PIN-42%PMN-32%PT perform the best among all materials. Compared with the pure crystal PIN47%PMN-29%PT, PMN-28%PT and PZT4 FT, the Mn:PIN-42%PMN32%PT FT has a decrease of total loss by 47.9%, 79.5% and 93.6%, respectively, under the same strain of 5 × 10−5. Fig. 4 also shows that Mn:PIN-PMN-PT FTs have significantly lower
fa2 − fr2 fa2
(4)
(1)
fr and fa were obtained from Fig. 3. keff for the five material FTs are calculated and listed in Table 3. Under the same condition, Table 3 shows that energy conversion capacity based on ternary and binary single crystals are higher than traditional piezoelectric material PZT4. Among the five materials, Mn:PIN-42%PMN-32%PT FT has the highest keff level, which is 7.2% higher than pure ternary PIN-47%PMN-29%PT FT. Compared Table 3 with Table 1, significant relativities between keff of FTs and k33 of their drive piezoelectric materials can be observed. This means that the higher k33 value of the piezoelectric material is, the higher keff of FT is. 2866
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3.3. The analysis of the TVR Transmitting Voltage Response (TVR), which is one of the indexes represent acoustic projector performances, specifies the amount of free field pressure produced for a 1 V signal applied across the electrical terminals of the transducer and referenced to a distance of 1 m [26]. The TVR of class IV FT is calculated as following:
TVR = 20log (pa ra/V ) + 120
(8)
where, pa is the acoustic pressure of FT; ra is the distance away from the FT along the acoustic axis in the far field. In-water TVR levels of class IV FTs based on the five materials are shown in Fig. 7 as a function of the frequency. Mn:PIN-42%PMN-32% PT FT possesses the highest TVR level while maintaining the better lowfrequency characteristic (2.6 kHz), its TVR value is 2 dB and 4 dB higher than Mn:PIN-47%PMN-29%PT FT and pure PIN-47%PMN-29% PT FT, respectively. PMN-28%PT FT is found to have similar TVR value as PIN-47%PMN-29%PT FT. PZT4 FT has the lowest TVR level. These results strongly imply that FTs based on the manganese-modified single crystals have better performance at TVR level.
Fig. 4. Mechanical losses level versus strain.
3.4. The analysis of the AP and SL As shown in Table 1, the coercive field is different for each drive material. Mn:PIN-42%PMN-32%PT, Mn:PIN-47%PMN-29%PT and PZT4 all have much higher Ec than PIN-47%PMN-29%PT and PMN28%PT. Therefore, in the analysis of AP and SL, the driving voltages that exerted on the piezoelectric stacks are different. Considering the limitation of the breakdown voltages, the maximum allowable driving fields for Mn:PIN-42%PMN-32%PT, Mn:PIN- 47%PMN-29%PT and PZT4 FTs are taken as 1100 V/mm. The maximum allowable driving fields for PIN-47%PMN-29%PT and PMN-28%PT FTs are taken as their Ec values. As one of the primary parameter of transducer, AP is also an important performance index. AP of class IV FTs based on the five materials are shown in Fig. 8. One can see that Mn:PIN-PMN-PT crystals behave sharply better than counterparts. In addition, acoustic radiated power, which is proportional to the square of AP, is also an important performance index and represents the electroacoustic transformation ability of transducer [23]. This means that the higher AP value can significantly increase acoustic radiated power. Therefore, FTs based on Mn:PIN-PMN-PT crystals will be more durable and efficient than other FTs based on PIN-47%PMN-29%PT, PMN-28%PT and PZT4. Fig. 9 illustrates the in-water source level of class IV FTs that actuated by all five materials. When the frequency is 2.6 kHz, the FT based on Mn:PIN-42%PMN-32%PT reached its peak value 204.2 dB of SL, which is also the highest SL value among all materials. As the frequency increase to 2.7 kHz, Mn:PIN-47%PMN-29%PT FT perform better than pure PIN-47%PMN-29%PT crystal FT. Under the frequency of 3.05 kHz, FT drive by PZT4 obtains the maximum SL of 197.5 dB, which is 6.7 dB less than Mn:PIN-42%PMN-32%PT. These results show that Mn:PIN-42%PMN-32%PT FT has the superiority of possessing simultaneously the higher SL and low resonant frequency.
Fig. 5. Dielectric losses level versus strain.
4. Conclusion In this paper, comprehensive analysis of a class IV FT driven by five materials are performed by considering simultaneously energy losses, admittance, bandwidth, TVR, SL and AP. Of particular important is the excellent comprehensive capacity of the FT driven by Mn:PIN-42% PMN-32%PT, its keff value can achieve more than 0.6 and its losses are the least among all five piezoelectric materials. Specifically, FTs based on the manganese-modified single crystals exhibit prominently in TVR, maximum SL and AP level. Furthermore, the effects of PT component on FTs for Mn:PIN-PMN-PT crystals are compared, even though the Mn:PIN-47%PMN-29%PT FT is slightly inferior to Mn:PIN-42%
Fig. 6. The total losses level versus strain.
mechanical losses than counterparts, and are less than twenty times mechanical loss of PMN-28%PT FT. This is attributed to the higher Qm values of Mn:PIN-PMN-PT single crystals. On the contrary, due to the low d33 and big dielectric loss factor, PZT4 FT has the maximum of the dielectric loss under the same strain. Fig. 6 indicated that Mn:PIN-PMNPT crystals possess lower total losses than other three counterparts. 2867
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Acknowledgements This research was supported by National Natural Science Foundation of China (Grant No. 51575344) and Shanghai Natural Science Foundation (Grant No. 14ZR1422000). Conflict of interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted. References [1] A.C. Hladky Hennion, A.E. Uzgur, R.E. Newnham, Monolithic class IV type flextensional transducers, J. Electroceram. 20 (3–4) (2008) 139–144. [2] H. Zhao, J. Ling, J. Yu, A comparative analysis of piezoelectric transducers for harvesting energy from asphalt pavement, J. Ceram. Soc. Jpn. 120 (1404) (2012) 317–323. [3] Y.G. Roh, K.K. Kang, Analysis and design of a flextensional transducer by means of the finite element method, Jpn. J. Appl. Phys. 47 (5) (2008) 3997–4002. [4] S.C. Thompson, R.J. Meyer, D.C. Markley, Performance of tonpilz transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient, J. Acoust. Soc. Am. 135 (1) (2014) 155–164. [5] S.J. Zhang, F. Li, J. Luo, R. Sahul, T. shrout, Relaxor-PbTiO3 single crystals for various applications, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 60 (8) (2013) 1573–1579. [6] G. Sebald, L. Lebrun, B. Guiffard, D. Guyomar, Morphotropic PMN-PT system investigated by comparison between ceramics and crystal, J. Eur. Ceram. Soc. 25 (12) (2005) 2509–2513. [7] M. Shanthi, L.C. Lim, K.K. Rajan, J. Jin, Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown [011]-poled Pb(Mg1/3Nb2/3)O3-(28-32)% PbTiO3 single crystals, Appl. Phys. Lett. 92 (14) (2008) 142906. [8] G. Liu, W. Jiang, J. Zhu, W. Cao, Electromechanical properties and anisotropy of single- and multi-domain 0.27Pb(Mg1/3Nb2/3)O3−0.28PbTiO3 single crystals, Appl. Phys. Lett. 99 (16) (2011) 162901. [9] S. Zhang, F. Li, High performance ferroelectric relaxor-PT single crystals: status and perspective, J. Appl. Phys. 111 (3) (2012) 031301. [10] S.J. Zhang, T.R. Shrout, Relaxor-PT single crystals: observations and developments, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 57 (10) (2010) 2138–2146. [11] M. Davis, Picturing the elephant: giant piezoelectric acitivity and the monoclinic phases of relaxor-ferroelectric single crystals, J. Electro Ceram. 19 (1) (2007) 23–45. [12] X.Q. Huo, S.J. Zhang, G. Liu, R. Zhang, J. Luo, R. Sahul, W.W. Cao, T.R. Shrout, Complete set of elastic, dielectric, and piezoelectric constants of [011]C poled rhombohedral Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3:Mn single crystals, J. Appl. Phys. 113 (2013) 074106. [13] N.P. Sherlock, R.J. Meyer, Modified single crystals for high-power underwater projectors, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 59 (6) (2012) 1285–1286. [14] E.W. Sun, W.W. Cao, Relaxor-based ferroelectric single crystals: growth, domain engineering, characterization and applications, Progress. Mater. Sci. 65 (10) (2014) 124–210. [15] E. Sun, R. Zhang, F. Wu, B. Yang, W. Cao, Influence of manganese doping to the full tensor properties of 0.24Pb(In1/2Nb1/2)O3-0.47Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals, J. Appl. Phys. 113 (7) (2013) 074108. [16] G. Liu, W. Jiang, J. Zhu, W.W. Cao, Electromechanical properties and anisotropy of single- and multi-domain 0.72Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 single crystals, Appl. Phys. Lett. 99 (16) (2011) 162901. [17] K.P.B. Moosad, G. Chandrashekar, M.J. Joseph, R. John, Class IV flextensional transducer with a reflector, Appl. Acoust. 72 (2–3) (2011) 127–131. [18] S.J. Zhang, F. Li, J. Luo, R. Xia, W. Hackenberger, T.R. Shrout, Field stability of piezoelectric shear properties in PIN-PMN-PT crystals under large drive field, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 58 (2) (2011) 274–280. [19] K.P.B. Moosad, P. Krishnakumar, G. Chandrashekar, R.M.R. Vishnubhatla, Frequency fine-tuning in Class IV flextensional transducers, Appl. Acoust. 68 (10) (2007) 1280–1285. [20] I. Hilibon, Underwater flextensional piezoceramic sandwich transducer, Sens. Actuators A Phys. 100 (2–3) (2002) 287–292. [21] T. Li, Y.H. Chen, F.Y.C. Boey, J. Ma, High amplitude vibration of piezoelectric bending actuators, J. Electroceram. 18 (3–4) (2007) 231–242. [22] W.C. Ou, S.Y. Li, W.W. Cao, M. Yang, A single-mode Mn-doped 0.27PIN-0.46PMN0.27PT single-crystal ultrasonic motor, J. Electroceram. 37 (1–4) (2016) 121–126. [23] S. Li, M. Yang, Analysis of the temperature field distribution for piezoelectric platetype ultrasonic motor, Sens. Actuators A Phys. 164 (1–2) (2010) 107–115. [24] IEEE Standard on Piezoelectricity, ANSI/IEEE STD, 1987, pp. 176-1987. [25] S.J. Zhang, F. Li, High performance ferroelectric relaxor-PbTiO3 single crystals: status and perspective, J. Appl. Phys. 111 (3) (2012) 031301. [26] B.P. Naidu, A.B. Rao, N.S. Prasad, K. Trinath, Low frequency acoustic projectors for underwater applications, Int. Ferroelectr. 118 (1) (2010) 84–94.
Fig. 7. The TVR levels of class IV FTs based on the five materials.
Fig. 8. The underwater AP of class IV FTs for five materials.
Fig. 9. The source level of Class IV FTs for five materials.
PMN-32%PT FT, both of them have significantly better properties than counterparts. Owing to these unique advantages, Mn:PIN-PMN-PT single crystals have immense potential in making less heat generation, low frequency and high power FT.
2868
Contents lists available at ScienceDirect
Ceramics International journal homepage: www.elsevier.com/locate/ceramint
Comprehensive analysis of Mn:PIN-PMN-PT single crystals for Class IV flextensional transducer ⁎
T
⁎
Rongjing Guoa, Shiyang Lia, , Dawei Ana, Tao Hana, Jing Chena, , Wenwu Caob a b
Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
A R T I C L E I N F O
A B S T R A C T
Keywords: Mn modified single crystal Heat generation High power Flextensional transducer
As a crucial part of flextensional transducer (FT), the piezoelectric stack has an essential influence on the transducer. However, up to date, there are no literatures on considering the loss characteristics of the piezoelectric materials in the design of FT. Manganese-modified PIN-PMN-PT (Mn:PIN-PMN-PT) single crystals have greatly improved Qm values compared with the binary and ternary single crystals. In this paper, Class IV FTs based on Mn:PIN-42%PMN-32%PT and Mn:PIN-47%PMN-29%PT crystals were analyzed comprehensively on the heat losses, as well as transmitting voltage response (TVR), source level (SL), acoustic pressure (AP) and admittance. Compared with PIN-47%PMN-29%PT, PMN-28%PT and PZT4, the Mn:PIN-42%PMN-32%PT FT has a decrease of heat loss by 47.9%, 79.5% and 93.6%, respectively, under the same strain of 5 × 10−5. The results indicated that the Mn:PIN-PMN-PT FT possesses simultaneously the less heat loss and lower resonant frequency, the higher AP, TVR, SL and effective electromechanical coupling coefficient. This research provides a guide for the design of FT and illuminates the immense potential of Mn:PIN-PMN-PT single crystals in making low heat generation, low frequency and high power FT.
1. Introduction The Class IV flextensional transducer (FT), which is a typical low frequency, high power and small size transducer, is widely applied in underwater acoustic projector [1]. Many researchers have focused on the design of the transducer structure. However, in the practical application, transducers usually work under the high driving voltage and vibration amplitude. Internal losses occur inevitably and are converted into heat [2]. High power and long term usage of the transducer will cause accumulation of the heat inside the transducer, which can result in temperature rise of the transducers [3]. Excessive temperature rise will seriously deteriorate the performance and the reliability life of the transducer. In recent years, heat problem has drawn considerable attentions. Roh and Kang simulated the effects of the shell sizes on the temperature of the FT by finite element method [3]. However, the effect of piezoelectric material dissipation for the transducer wasn't considered. As a crucial part that transform electrical energy to mechanical energy, the properties and thermal loss of piezoelectric material have an essential influence on the transducer in high power applications. For the underwater transducers, the features of lower driving frequency, wider frequency band and less power loss are desired. Therefore, it is necessary to consider the loss characteristics of the piezoelectric
⁎
materials, as well as the acoustic parameters in the design of the FT. Over the past decades, relaxor-based single crystals have attracted much attention owing to their ultrahigh piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 0.90). The first generation single crystals, such as Pb(Mg1/3Nb2/ 3)O3-PbTiO3 (PMN-PT), have been used in Tonpilz transducer [4]. Compared with conventional Pb(Zr,Ti)O3 (PZT) piezoelectric ceramics, PMN-PT has been demonstrated to possess improvements of the bandwidth and source level of the transducers [5–11]. However, the binary crystals possess low coercive field Ec (~ 2–3 kV/cm), low mechanical quality factor Qm (~ 190), low rhombohedral-to-tetragonal phase transition temperature (TRT ~ 60–100 °C), restricting their practical applications in the high power transducer. The second generation single crystals, ternary Pb(In1/2Nb1/2)O3-Pb(Mb1/3Nb2/3)O3-PbTiO3 (PINPMN-PT), have higher TC (being on the order of 180–220 °C), and higher coercive field Ec (being on the order of ~ 5 kV/cm) than PMNPT, showing much improvement of temperature stability and electric field stability, while maintaining the competence in piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 0.90) [11]. For high power applications, high Qm value is desired to reduce heat generation. However, PIN-PMN-PT has not improved much in the Qm value (~ 290).
Corresponding authors. E-mail addresses: [email protected] (S. Li), [email protected] (J. Chen).
http://dx.doi.org/10.1016/j.ceramint.2017.11.033 Received 2 October 2017; Received in revised form 30 October 2017; Accepted 6 November 2017 Available online 07 November 2017 0272-8842/ © 2017 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Ceramics International 44 (2018) 2864–2868
R. Guo et al.
Table 2 The sizes of the class IV FT. Parameter (mm)
Parameter (mm)
Semi Minor axis length Shell thickness Piezoelectric stack length
36 8 28.5
Semi major axis length Shell height Piezoelectric stack radius
72 90 8
Mn:PIN-47%PMN-29%PT single crystals, as well as PIN-47%PMN-29% PT, PMN-28%PT and PZT4, are listed and compared in Table 1. MaT T terial parameters ρ , TRT, d33, ε33 , k33, Ec, Qm, tanδ , s33 represent density, rhombohedral-to-tetragonal phase transition temperatures, piezoelectric coefficient relating strain/electric field, dielectric permittivity, coercive field, mechanical quality factor, dielectric loss factor and elastic compliance constant, respectively. In order to calculate conveniently, one eighth of the whole finite element model is set up using commercial finite element software ANSYS. The sizes are shown in Table 2. The models in air and water environment are shown in Fig. 2. In this model, the aluminum material and stainless steel are applied on the cylindrical shell and transition structure, respectively. The piezoelectric materials listed in Table 1 are selected as the drive materials. In addition, fluid-structure coupling load was imposed on the fluid-structure interface (FSI) layer, which represents the interaction between the water and the transducer. Then all the analyses are performed in water environment.
Fig. 1. The whole finite element transducer model in air.
Recently, the third generation crystals, manganese-modified PINPMN-PT (Mn:PIN-PMN-PT) crystals have greatly improved Qm value (~ 810), which is comparable to that of the hard PZT ceramics. Compared with the ternary single crystals, Mn:PIN-PMN-PT has similar piezoelectric properties. Considering of much enhanced Qm value and a moderate increment in the phase transition temperature by the addition of Mn, together with the comparable piezoelectric and electromechanical properties, Mn:PIN-PMN-PT single crystal will be a potential candidate for high power FT. However, up to date, there are no reports in the literature on the effects of Mn:PIN-PMN-PT single crystal on FT by considering simultaneous energy losses and underwater acoustic properties. In this work, comprehensive analysis of a class IV FT based on Mn:PIN-PMN-PT crystals is performed. The effects of PT component for Mn:PIN-PMN-PT crystals (Mn:PIN-42%PMN-32%PT and Mn:PIN-47% PMN-29%PT) on the FTs are discussed. Meanwhile, the properties of the class IV FTs based on Mn:PIN-PMN-PT crystals are investigated and compared with binary PMN-PT crystal, ternary PIN-PMN-PT crystal, and conventional PZT ceramic by considering simultaneously energy losses, admittance, bandwidth, transmitting voltage response (TVR), source level (SL) and acoustic pressure (AP). The intent of this work is to perform a global analysis and illuminate the potential of Mn:PINPMN-PT single crystal in making less energy loss, low frequency and high power FTs.
3. Results and discussions For the underwater transducers, general characterization that includes corresponding admittance spectrum, TVR, SL, AP are investigated to evaluate the performance of transducer. 3.1. The analysis of the admittance The in-water admittance spectra of FTs based on the five materials are simulated and shown in Fig. 3. The peaks with maximum and minimum admittance corresponds to the resonant frequency fr and antiresonant frequency fa of the FTs, respectively. Generally, the resonant frequency is mainly determined by shell shape of the transducer [19]. However, because the shells are the same in all simulations for the five drive materials in this paper, the differences of admittance curves of FTs are mainly caused by its drive materials. The differences of the resonant frequencies of FT based on the five piezoelectric materials can also be observed from Fig. 3. The FTs driven by all four single crystals present lower frequencies than PZT4 PT. Among these crystals, the Mn:PIN-PMN-PT transducers exhibit better low-frequency performances than counterparts. Especially, the Mn:PIN42%PMN-32%PT FT, which possesses the lowest resonance frequency, is 150 Hz and 450 Hz lower than PMN-28%PT and PZT4 FTs, respectively. This demonstrated that the manganese-modified crystal is the most appropriate choice for fabricating low frequency FTs. In addition, the effective electromechanical coupling coefficient (keff), which is a key parameter to evaluate the performance of transducer and represents the energy conversion capacity, can be calculated
2. Model and material constants of the transducer In our works, Class IV FT consists of a pair of cylindrical piezoelectric stack that serve as the active driver and an elliptical shell that serves as an acoustic radiator, just as shown in Fig. 1. Because of the displacement amplification effect provided by elliptic shell based on leverage effect, small extensional displacement produced by piezoelectric stacks is transmitted into large volume displacement on the elliptical shell, which can output the acoustic radiated power. To address the effect and the advantage of Mn:PIN-PMN-PT crystal on the FT, the material properties of Mn:PIN-42%PMN-32%PT,
Table 1 The characteristics comparison of Mn:PIN-PMN-PT, PMN-PT, PIN-PMN-PT single crystals and PZT4 [9,12–18]. Material
Mn:PIN-42%PMN-32%PT Mn:PIN-47%PMN-29%PT PIN-47%PMN-29%PT PMN-28%PT PZT4
ρ
TRT
d33
Ec
Qm,
pC/N
/
kV/cm
%
T s33 10−12 m2/N
tanδ
°C
T ε33 ε0
k33
kg/m2 8100 8173 8122 8095 7500
128 128 125 95 /
1341 855 1285 1182 289
3811 2599 4753 5479 1300
0.92 0.86 0.89 0.91 0.74
11.5 11.5 5.0 2.5 14
810 810 290 190 500
64.96 43.07 49.04 34.30 15.0
0.16 0.16 0.15 0.26 0.3
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Fig. 2. One eighth of the whole finite element transducer model of the Class IV FT: (a) in air environment, (b) in water environment.
3.2. The analysis of energy loss In FTs, the energy loss generally includes the dielectric and mechanical loss, shown as follows [21–23]:
Qgen = Qmec + Qele
(2)
where Qmec and Qele are the mechanical loss and electrical loss, respectively. Because the shell is the same in the analysis of the different piezoelectric stack, the mechanical loss of the shell is regarded as identical under the same shell strain. So, we mainly focus on the effects of the each piezoelectric materials on FTs, the mechanical loss of only the piezoelectric stack is considered as [21–23]:
Qmec =
1 ωT3 S3 VPS 2Qm
(3)
where, T3 and S3 represent stress and strain, respectively; ω is angular frequency and is equal to 2πf ; VPS is the volume of the piezoelectric stack. T3 and S3 are shown as following [24,25]: Fig. 3. The admittance spectra of IV FTs for five kinds of materials.
T3 =
Table 3 Comparison of the electromechanical coupling coefficient (keff) of FTs with different drive materials. Materials
fr(Hz)
fa(Hz)
keff
Mn:PIN-42%PMN-32%PT Mn:PIN-47%PMN-29%PT PIN-47%PMN-29% PMN-28%P PZT4
2550 2650 2650 2750 2950
3200 3150 3200 3350 3250
0.604 0.540 0.560 0.571 0.419
1 S − e33 E3 E 3 S33
S3 = d33 E3
(5)
E3 = V / d
(6)
where V, e33 , E3 and d present the driving voltage, piezoelectric coefficient relating stress/electric field, electric-field magnitude and the thickness of stack piece, respectively. As a part of the energy loss, the dielectric loss can be calculated as [21–23]:
Qele = as follows [20]:
keff =
1 2 T E3 ωε33tanδVPS 2 T ε33
(7)
and tanδ is the dielectric permittivity and dielectric loss where factor, respectively. Because the strain of the piezoelectric stack is proportional to the output displacement of transducer, the strain of the piezoelectric stack is used in the analysis of the energy loss. According to Eqs. (2)–(7), the relationships of the energy loss and strain for all five piezoelectric materials are obtained and shown in Figs. 4–6. These figures exhibit an exponential growth of the losses with the increase of strain. For three types of the losses, the transducer with Mn:PIN-42%PMN-32%PT perform the best among all materials. Compared with the pure crystal PIN47%PMN-29%PT, PMN-28%PT and PZT4 FT, the Mn:PIN-42%PMN32%PT FT has a decrease of total loss by 47.9%, 79.5% and 93.6%, respectively, under the same strain of 5 × 10−5. Fig. 4 also shows that Mn:PIN-PMN-PT FTs have significantly lower
fa2 − fr2 fa2
(4)
(1)
fr and fa were obtained from Fig. 3. keff for the five material FTs are calculated and listed in Table 3. Under the same condition, Table 3 shows that energy conversion capacity based on ternary and binary single crystals are higher than traditional piezoelectric material PZT4. Among the five materials, Mn:PIN-42%PMN-32%PT FT has the highest keff level, which is 7.2% higher than pure ternary PIN-47%PMN-29%PT FT. Compared Table 3 with Table 1, significant relativities between keff of FTs and k33 of their drive piezoelectric materials can be observed. This means that the higher k33 value of the piezoelectric material is, the higher keff of FT is. 2866
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3.3. The analysis of the TVR Transmitting Voltage Response (TVR), which is one of the indexes represent acoustic projector performances, specifies the amount of free field pressure produced for a 1 V signal applied across the electrical terminals of the transducer and referenced to a distance of 1 m [26]. The TVR of class IV FT is calculated as following:
TVR = 20log (pa ra/V ) + 120
(8)
where, pa is the acoustic pressure of FT; ra is the distance away from the FT along the acoustic axis in the far field. In-water TVR levels of class IV FTs based on the five materials are shown in Fig. 7 as a function of the frequency. Mn:PIN-42%PMN-32% PT FT possesses the highest TVR level while maintaining the better lowfrequency characteristic (2.6 kHz), its TVR value is 2 dB and 4 dB higher than Mn:PIN-47%PMN-29%PT FT and pure PIN-47%PMN-29% PT FT, respectively. PMN-28%PT FT is found to have similar TVR value as PIN-47%PMN-29%PT FT. PZT4 FT has the lowest TVR level. These results strongly imply that FTs based on the manganese-modified single crystals have better performance at TVR level.
Fig. 4. Mechanical losses level versus strain.
3.4. The analysis of the AP and SL As shown in Table 1, the coercive field is different for each drive material. Mn:PIN-42%PMN-32%PT, Mn:PIN-47%PMN-29%PT and PZT4 all have much higher Ec than PIN-47%PMN-29%PT and PMN28%PT. Therefore, in the analysis of AP and SL, the driving voltages that exerted on the piezoelectric stacks are different. Considering the limitation of the breakdown voltages, the maximum allowable driving fields for Mn:PIN-42%PMN-32%PT, Mn:PIN- 47%PMN-29%PT and PZT4 FTs are taken as 1100 V/mm. The maximum allowable driving fields for PIN-47%PMN-29%PT and PMN-28%PT FTs are taken as their Ec values. As one of the primary parameter of transducer, AP is also an important performance index. AP of class IV FTs based on the five materials are shown in Fig. 8. One can see that Mn:PIN-PMN-PT crystals behave sharply better than counterparts. In addition, acoustic radiated power, which is proportional to the square of AP, is also an important performance index and represents the electroacoustic transformation ability of transducer [23]. This means that the higher AP value can significantly increase acoustic radiated power. Therefore, FTs based on Mn:PIN-PMN-PT crystals will be more durable and efficient than other FTs based on PIN-47%PMN-29%PT, PMN-28%PT and PZT4. Fig. 9 illustrates the in-water source level of class IV FTs that actuated by all five materials. When the frequency is 2.6 kHz, the FT based on Mn:PIN-42%PMN-32%PT reached its peak value 204.2 dB of SL, which is also the highest SL value among all materials. As the frequency increase to 2.7 kHz, Mn:PIN-47%PMN-29%PT FT perform better than pure PIN-47%PMN-29%PT crystal FT. Under the frequency of 3.05 kHz, FT drive by PZT4 obtains the maximum SL of 197.5 dB, which is 6.7 dB less than Mn:PIN-42%PMN-32%PT. These results show that Mn:PIN-42%PMN-32%PT FT has the superiority of possessing simultaneously the higher SL and low resonant frequency.
Fig. 5. Dielectric losses level versus strain.
4. Conclusion In this paper, comprehensive analysis of a class IV FT driven by five materials are performed by considering simultaneously energy losses, admittance, bandwidth, TVR, SL and AP. Of particular important is the excellent comprehensive capacity of the FT driven by Mn:PIN-42% PMN-32%PT, its keff value can achieve more than 0.6 and its losses are the least among all five piezoelectric materials. Specifically, FTs based on the manganese-modified single crystals exhibit prominently in TVR, maximum SL and AP level. Furthermore, the effects of PT component on FTs for Mn:PIN-PMN-PT crystals are compared, even though the Mn:PIN-47%PMN-29%PT FT is slightly inferior to Mn:PIN-42%
Fig. 6. The total losses level versus strain.
mechanical losses than counterparts, and are less than twenty times mechanical loss of PMN-28%PT FT. This is attributed to the higher Qm values of Mn:PIN-PMN-PT single crystals. On the contrary, due to the low d33 and big dielectric loss factor, PZT4 FT has the maximum of the dielectric loss under the same strain. Fig. 6 indicated that Mn:PIN-PMNPT crystals possess lower total losses than other three counterparts. 2867
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Acknowledgements This research was supported by National Natural Science Foundation of China (Grant No. 51575344) and Shanghai Natural Science Foundation (Grant No. 14ZR1422000). Conflict of interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted. References [1] A.C. Hladky Hennion, A.E. Uzgur, R.E. Newnham, Monolithic class IV type flextensional transducers, J. Electroceram. 20 (3–4) (2008) 139–144. [2] H. Zhao, J. Ling, J. Yu, A comparative analysis of piezoelectric transducers for harvesting energy from asphalt pavement, J. Ceram. Soc. Jpn. 120 (1404) (2012) 317–323. [3] Y.G. Roh, K.K. Kang, Analysis and design of a flextensional transducer by means of the finite element method, Jpn. J. Appl. Phys. 47 (5) (2008) 3997–4002. [4] S.C. Thompson, R.J. Meyer, D.C. Markley, Performance of tonpilz transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient, J. Acoust. Soc. Am. 135 (1) (2014) 155–164. [5] S.J. Zhang, F. Li, J. Luo, R. Sahul, T. shrout, Relaxor-PbTiO3 single crystals for various applications, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 60 (8) (2013) 1573–1579. [6] G. Sebald, L. Lebrun, B. Guiffard, D. Guyomar, Morphotropic PMN-PT system investigated by comparison between ceramics and crystal, J. Eur. Ceram. Soc. 25 (12) (2005) 2509–2513. [7] M. Shanthi, L.C. Lim, K.K. Rajan, J. Jin, Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown [011]-poled Pb(Mg1/3Nb2/3)O3-(28-32)% PbTiO3 single crystals, Appl. Phys. Lett. 92 (14) (2008) 142906. [8] G. Liu, W. Jiang, J. Zhu, W. Cao, Electromechanical properties and anisotropy of single- and multi-domain 0.27Pb(Mg1/3Nb2/3)O3−0.28PbTiO3 single crystals, Appl. Phys. Lett. 99 (16) (2011) 162901. [9] S. Zhang, F. Li, High performance ferroelectric relaxor-PT single crystals: status and perspective, J. Appl. Phys. 111 (3) (2012) 031301. [10] S.J. Zhang, T.R. Shrout, Relaxor-PT single crystals: observations and developments, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 57 (10) (2010) 2138–2146. [11] M. Davis, Picturing the elephant: giant piezoelectric acitivity and the monoclinic phases of relaxor-ferroelectric single crystals, J. Electro Ceram. 19 (1) (2007) 23–45. [12] X.Q. Huo, S.J. Zhang, G. Liu, R. Zhang, J. Luo, R. Sahul, W.W. Cao, T.R. Shrout, Complete set of elastic, dielectric, and piezoelectric constants of [011]C poled rhombohedral Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3:Mn single crystals, J. Appl. Phys. 113 (2013) 074106. [13] N.P. Sherlock, R.J. Meyer, Modified single crystals for high-power underwater projectors, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 59 (6) (2012) 1285–1286. [14] E.W. Sun, W.W. Cao, Relaxor-based ferroelectric single crystals: growth, domain engineering, characterization and applications, Progress. Mater. Sci. 65 (10) (2014) 124–210. [15] E. Sun, R. Zhang, F. Wu, B. Yang, W. Cao, Influence of manganese doping to the full tensor properties of 0.24Pb(In1/2Nb1/2)O3-0.47Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystals, J. Appl. Phys. 113 (7) (2013) 074108. [16] G. Liu, W. Jiang, J. Zhu, W.W. Cao, Electromechanical properties and anisotropy of single- and multi-domain 0.72Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 single crystals, Appl. Phys. Lett. 99 (16) (2011) 162901. [17] K.P.B. Moosad, G. Chandrashekar, M.J. Joseph, R. John, Class IV flextensional transducer with a reflector, Appl. Acoust. 72 (2–3) (2011) 127–131. [18] S.J. Zhang, F. Li, J. Luo, R. Xia, W. Hackenberger, T.R. Shrout, Field stability of piezoelectric shear properties in PIN-PMN-PT crystals under large drive field, IEEE Trans. Ultrason. Ferroelectr. Freq. Control. 58 (2) (2011) 274–280. [19] K.P.B. Moosad, P. Krishnakumar, G. Chandrashekar, R.M.R. Vishnubhatla, Frequency fine-tuning in Class IV flextensional transducers, Appl. Acoust. 68 (10) (2007) 1280–1285. [20] I. Hilibon, Underwater flextensional piezoceramic sandwich transducer, Sens. Actuators A Phys. 100 (2–3) (2002) 287–292. [21] T. Li, Y.H. Chen, F.Y.C. Boey, J. Ma, High amplitude vibration of piezoelectric bending actuators, J. Electroceram. 18 (3–4) (2007) 231–242. [22] W.C. Ou, S.Y. Li, W.W. Cao, M. Yang, A single-mode Mn-doped 0.27PIN-0.46PMN0.27PT single-crystal ultrasonic motor, J. Electroceram. 37 (1–4) (2016) 121–126. [23] S. Li, M. Yang, Analysis of the temperature field distribution for piezoelectric platetype ultrasonic motor, Sens. Actuators A Phys. 164 (1–2) (2010) 107–115. [24] IEEE Standard on Piezoelectricity, ANSI/IEEE STD, 1987, pp. 176-1987. [25] S.J. Zhang, F. Li, High performance ferroelectric relaxor-PbTiO3 single crystals: status and perspective, J. Appl. Phys. 111 (3) (2012) 031301. [26] B.P. Naidu, A.B. Rao, N.S. Prasad, K. Trinath, Low frequency acoustic projectors for underwater applications, Int. Ferroelectr. 118 (1) (2010) 84–94.
Fig. 7. The TVR levels of class IV FTs based on the five materials.
Fig. 8. The underwater AP of class IV FTs for five materials.
Fig. 9. The source level of Class IV FTs for five materials.
PMN-32%PT FT, both of them have significantly better properties than counterparts. Owing to these unique advantages, Mn:PIN-PMN-PT single crystals have immense potential in making less heat generation, low frequency and high power FT.
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