BCTZ첨가가 NKLN-AS계 압전세라믹스의 미세구조와 압전/유전특성 및 상전이현상에 미치는 효과

이웅재,어순철,이영근,윤만순,Lee, Woong-Jae,Ur, Soon-Chul,Lee, Young-Geun,Yoon, Man-Soon 한국재료학회 2012 한국재료학회지 Vol.22 No.1

Presently, the most promising family of lead-free piezoelectric ceramics is based on $K_{0.5}Na_{0.5}NbO_3$(KNN). Lithium, silver and antimony co-doped KNN ceramics show high piezoelectric properties at room temperature, but often suffer from abnormal grain growth. In the present work, the $(Ba_{0.85}Ca_{0.15})(Ti_{0.88}Zr_{0.12})O_3$ component, which has relaxor ferroelectric characteristics, was doped to suppress the abnormal grain growth. To investigate this effect, Lead-Free $0.95(K_{0.5}Na_{0.5})_{0.95}Li_{0.05}NbO_3-(0.05-x)AgSbO_3-x(Ba_{0.85}Ca_{0.15})(Ti_{0.88}Zr_{0.12})O_3$[KNLN-AS-xBCTZ] piezoelectric ceramics were synthesized by ball mill and nanosized-milling processes in lead-Free $0.95(K_{0.5}Na_{0.5})_{0.95}Li_{0.05}NbO_3-(0.05-x)AgSbO_3$ in order to suppress the abnormal grain growth. The nanosized milling process of calcined powders enhanced the sintering density. The phase structure, microstructure, and ferroelectric and piezoelectric properties of the KNLN-AS ceramics were systematically investigated. XRD patterns for the doped and undoped samples showed perovskite phase while tetragonality was increased with increasing BCZT content, which increase was closely related to the decrease of TO-T. Dense and uniform microstructures were observed for all of the doped BCZT ceramics. After the addition of BCTZ, the tetragonal-cubic and orthorhombic-tetragonal phase transitions shifted to lower temperatures compared to those for the pure KNNL-AS. A coexistence of the orthorhombic and tetragonal phases was hence formed in the ceramics with x = 0.02 mol at room temperature, leading to a significant enhancement of the piezoelectric properties. For the composition with x = 0.02 mol, the piezoelectric properties showed optimum values of: $d_{33}$ = 185 pC/N, $k_P$ = 41%, $T_C=325^{\circ}C$, $T_{O-T}=-4^{\circ}C$.

Enhanced piezoelectric output performance via control of dielectrics in Fe²⁺-incorporated MAPbI₃ perovskite thin films: Flexible piezoelectric generators

Ippili, Swathi,Jella, Venkatraju,Kim, Jaegyu,Hong, Seungbum,Yoon, Soon-Gil Elsevier 2018 Nano energy Vol.49 No.-

<P><B>Abstract</B></P> <P>We report a high-performance flexible piezoelectric generator (PEG) that was based on organic-inorganic lead halide perovskite materials and is operated by controlling the dielectric constant via the partial substitution of Pb<SUP>2+</SUP> with Fe<SUP>2+</SUP> in MAPbI<SUB>3</SUB>. The partial replacement of Pb<SUP>2+</SUP> with Fe<SUP>2+</SUP> improved both the morphology and crystallinity of MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (0.01 ≤ x ≤ 0.50) films that undergo a tetragonal-cubic phase transition above an incorporated concentration of Fe<SUP>2+</SUP> (x > 0.07). In addition, the phase transition temperatures of MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (0.01 ≤ x ≤ 0.07) films linearly decreased as a function of incorporated concentration, which resulted in a transition temperature for MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) of ~ 45.5 ± 1.5 °C. The dielectric properties as a function of incorporated concentration at room temperature suggested that MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) exhibited a dielectric constant of ~107 and a dissipation factor of 0.02 at 100 kHz. The MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) films exhibited a low leakage current density of ~ 10<SUP>−6</SUP> at a high applied electric field of 40 kV/cm, and the resultant remanent polarization from saturated ferroelectric P-E hysteresis loops was ~ 1.6 µC/cm<SUP>2</SUP>. The MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) flexible PEG improved output performance by ~ 7.29 V and current density by ~ 0.88 µA/cm<SUP>2</SUP> after poling at 30 kV/cm. This was sufficient to instantly light a commercial light-emitting diode (LED) without a storage device. This approach provides a framework that enhances the output performance of organic-inorganic metal halide perovskite materials-based piezoelectric energy harvesters, which could help pave the road to viable, self-powered, wearable electronics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High performance flexible piezoelectric generator using MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (0.01 ≤ x ≤ 0.07) films. </LI> <LI> Phase transition temperature of MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) is ~ 45.5 ± 1.5 °C. </LI> <LI> MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) films having a predominate dielectric property. </LI> <LI> MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) PEG having output voltage of ~ 7.29 V and current density of ~ 0.88 µA/cm<SUP>2</SUP>. </LI> <LI> Instantly lightening of a commercial light-emitting diode (LED) without a storage device. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The partial replacement of Pb<SUP>2+</SUP> with Fe<SUP>2+</SUP> in MAPbI<SUB>3</SUB> perovskite films showed the significant improvement in dielectric properties as well as piezoelectric output performance at the dopant range of x = 0.07. In particular, high-performance flexible piezoelectric generator was fabricated using MAPb<SUB>1-x</SUB>Fe<SUB>x</SUB>I<SUB>3</SUB> (x = 0.07) perovskite film. The output voltage and current density of PEG were 7.29 V and 0.88 µA/cm<SUP>2</SUP>, respectively.</P> <P>[DISPLAY OMISSION]</P>

Enhancement of piezoelectric and ferroelectric properties of BaTiO₃ ceramics by aluminum doping

Ali, Ahmed I.,Ahn, Chang Won,Kim, Yong Soo Elsevier 2013 Ceramics international Vol.39 No.6

<P><B>Abstract</B></P> <P>Ferroelectric and piezoelectric properties of BaTiO<SUB>3</SUB> and Al-doped BaTiO<SUB>3</SUB> ceramics were investigated. The ferroelectric study demonstrated that, by doping Al<SUP>3+</SUP> ions in the A-site of BaTiO<SUB>3</SUB>, the polarization–electric field loop exhibited enhanced remnant polarization (from 12 to 17.5 μC/cm<SUP>2</SUP>), saturation and switching. In addition, the piezoelectric constant (<I>d</I> <SUB>33</SUB>) increased with Al-doping for both static and dynamic strain values (from 75 to 135 and from 29.2 to 57.9pC/N, respectively, at a maximum applied electric field of 16kV/cm). Furthermore, the dielectric constant values increased and both the dielectric loss factor and leakage current decreased, even though the transition temperature shifted to lower temperature (from 121 to 113°C) for the Al-doped sample. Therefore, the Al-doped BaTiO<SUB>3</SUB> has adjustable piezoelectric and ferroelectric properties.</P>

Improved aging behavior of lead-free (Na,K)NbO₃-LiSbO₃ piezoelectric actuators

Kim, J.,Koh, J.H. Ceramurgica ; Elsevier Science Ltd 2017 Ceramics international Vol.43 No.suppl1

Due to environmental concerns, lead-free or lead-content-reduced materials among the piezoelectric materials have been extensively studied with great attention. (Na<SUB>0.5</SUB>K<SUB>0.5</SUB>)NbO<SUB>3</SUB> (NKN) piezoelectric material has been a representative material for lead-free piezoelectric ceramics, due to its good piezoelectric properties. Adding LiSbO<SUB>3</SUB> in the form of lithium ion (Li<SUP>+</SUP>) and antimony ion (Sb<SUP>5+</SUP>) into the A-site and B-site of NKN ceramics solved the evaporation and poling problems. In this paper, after the fabrication of (Na<SUB>0.5</SUB>K<SUB>0.5</SUB>)NbO<SUB>3</SUB>-LiSbO<SUB>3</SUB> (NKN-LS) piezoelectric ceramics, regular electric fields of AC bias were applied to the NKN-LS ceramics. Applying bias led to piezoelectric actuators losing their piezoelectric and dielectric properties. The surface microstructure and piezoelectric properties were compared and analyzed before and after the aging process. Adding LS contents retarded the aging rate of NKN-LS, compared with that of NKN ceramics.

Reactive Sintering of (K0.5Bi0.5)TiO3-BiFeO3 Lead-free Piezoelectric Ceramics

John Gerard Fisher,김민구,김대웅,차수정,Hung Van Vu,Dieu Nguyen,김영훈,문수현,이종숙,Ali Hussain,김명호 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.9

Ceramics based on BiFeO3 are potential lead-free replacements for Pb(Zr,Ti)O3 in a variety of applications such as sensors, transducers and actuators. Recently, ceramics in the (K0.5Bi0.5)TiO3- BiFeO3 system were developed which have excellent piezoelectric properties. However, these ceramics are difficult to sinter to high density. The present work studies the use of reactive sintering to prepare 0.4(K0.5Bi0.5)TiO3-0.6BiFeO3 ceramics. Undoped and MnO-doped powders were prepared by ball milling K2CO3, (BiO)2CO3, TiO2, α-FeO(OH) and MnCO3 in ethanol with zirconia milling media. The decomposition and calcination reactions of the starting materials were studied using differential scanning calorimetry/thermogravimetric analysis, X-ray diffraction and Fourier transform infra-red analysis. Samples were sintered in the temperature range from 1000 to 1075 ◦ C and their structures and microstructures examined using X-ray diffraction, micro-Raman scattering and scanning electron microscopy. MnO doping reduced the rhombohedral distortion of the unit cell. The dielectric, ferroelectric and piezoelectric properties of selected undoped and MnO-doped samples were measured. Both undoped and MnO-doped samples displayed relaxor-type behavior. MnO doping reduced the conductivity of the samples, which exhibit a well-defined activation energy of 1.21 eV. Undoped samples have strain vs. electric field properties comparable to those reported in the literature.

Low-temperature sintering and piezoelectric properties of CuO-doped (K,Na)NbO₃ ceramics

Kim, J.H.,Kim, J.S.,Han, S.H.,Kang, H.-W.,Lee, H.-G.,Cheon, C.I. Elsevier 2017 Materials research bulletin Vol.96 No.2

<P><B>Abstract</B></P> <P>The lead-free piezoelectric [(K<SUB>0.485</SUB>Na<SUB>0.515</SUB>)<SUB>0.935</SUB>Li<SUB>0.065</SUB>](Nb<SUB>0.99</SUB>Ta<SUB>0.01</SUB>)O<SUB>3</SUB> (KNLNT) ceramics with a high mechanical quality factor (Q<SUB>m</SUB>) were prepared at low sintering temperature below 950°C for multilayered piezoelectric devices. Co-doping effect of 1mol% Na<SUB>2</SUB>CO<SUB>3</SUB> and 0–1mol% CuO on the densification and piezoelectric properties were investigated. Co-doping effectively decreased the sintering temperature of KNLNT ceramics to 920°C. The co-doped KNLNT ceramics had a bimodal size distribution of large abnormal grains and small matrix grains above 900°C. When the sintering temperature increased above 900°C, a dielectric constant (ε<SUB>r</SUB>) and loss (tan δ) decreased considerably and concurrently mechanical quality factor (Q<SUB>m</SUB>) greatly enhanced. The co-doped KNLNT ceramic with 1mol% Na<SUB>2</SUB>CO<SUB>3</SUB> and 0.5mol% CuO had a high Q<SUB>m</SUB> and excellent piezoelectric properties when sintered at 940°C: a dielectric constant of 245 and loss (tan δ) of 0.0034, an electromechanical coupling factor (<I>k</I> <SUB>p</SUB>) of 0.449, and Q<SUB>m</SUB> of 904.</P> <P><B>Highlights</B></P> <P> <UL> <LI> KNN-based lead-freepiezoelectric ceramics was fabricated at the sintering temperature below 950°C by co-doping with Na<SUB>2</SUB>CO<SUB>3</SUB> and CuO for multilayered piezoelectric devices. </LI> <LI> The co-doped sample has not only a high mechanical quality factor (Q<SUB>m</SUB>) over 900 but also excellent piezoelectric properties. </LI> <LI> Mechanisms on micostructure development and the change in piezoelectric properties with the sintering temperature were proposed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effects of Ti nonstoichiometry on microstructure, dielectric, ferroelectric and piezoelectric properties of (Na0.54Bi0.5)0.94Ba0.06Ti1+xO3 lead-free ceramics

Xu-mei Zhao,Xiao-Ming Chen,Jian Wang,Xiao-xia Liang,Jian-Ping Zhou,Peng Liu 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1

The lead-free ceramics (Na0.54Bi0.5)0.94Ba0.06Ti1+xO3 with x = −0.02, 0, 0.02, and 0.04 were prepared by a solid-state reaction method. Effects of Ti4+ nonstoichiometry on crystallite structure, microstructure, dielectric, ferroelectric and piezoelectric properties were studied. The ceramics with x = −0.02 and 0 exhibit typical diffraction peaks of perovskite structure. A secondary phase appears in the ceramics with x = 0.02 and 0.04. The rhombohedral-tetragonal morphotropic phase boundary exists in all samples, and the relative amount of the tetragonal phase changes with the increase in the Ti4+ amount from deficiency to excess. Grain sizes and shape of the ceramics are unaffected by changes in Ti4+ nonstoichiometry. But, dielectric, ferroelectric and piezoelectric properties of the ceramics are close related to the Ti4+ amounts. Compared with the ceramic with x = 0, the ceramics with the Ti4+ nonstoichiometry have higher depolarization temperature, lower maximum dielectric constant, decreased piezoelectric constant and ferroelectric properties.

Electrical Properties of Lead-free 0.98(Na0.5K0.5Lix)NbO3-0.02Ba(Zr0.52Ti0.48)O3 Ceramics

이승환,Hyun-Ju Kim,이성갑,고중혁,Sang-Don Baek,이영희 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.1

Lead-free 0.98(Na0.5K0.5Lix)NbO3-0.02Ba(Zr0.52Ti0.48)O3 piezoelectric ceramics were investigated. The experimental results show that Li content strongly affects the orthorhombic-tetragonal morphotropic phase boundary (MPB) which results in different piezoelectric properties. The phase transition composition shows a range from 0.05 to 0.1. The sample with a composition of x = 0.1 showed the maximum values of piezoelectric coefficient (d33= 201 ρC/N), electromechanical coupling coefficient (kp= 39%), and remnant polarization (Pr= 21 μC/cm2).

Dielectric and Ferroelectric Properties of LiNbO_3 Doped Lead-free Bi_(0.5)Na_(0.5)TiO_3 (BNT) Ceramics

김진수,정창희,이호섭,정수태 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.31

To investigate the effect of LiNbO_3 doping on Bi_(0.5)Na_(0.5)TiO_3 (BNT), we prepared LiNbO_3 doped (1-x)Bi_(0.5)Na_(0.5)TiO_3: xLiNbO_3 (BNT:LN) ceramics by using a solid-state reaction method. Wellcrystallized lead-free BNT and BNT:LN ceramics formed a single phase with a perovskite structure. LiNbO_3 doping of Bi_(0.5)Na_(0.5)TiO_3 affected the dielectric behaviors and the ferroelectric properties. With increasing LiNbO_3 doping, the dielectric peak at the temperature of T_m = 340 ℃ broadened and shifted to low temperature. The ferroelectric polarization measurement indicated that a ferroelectric phase changed to a paraelectric phase, and the well saturated polarization-electric field (P-E) hysteresis loops exhibited at x = 0.03 ∼ 0.05. In this work, the effects of LiNbO_3 doping on the dielectric and the ferroelectric properties were investigated by using X-ray diffraction, scanning electron microscopy, grain morphology, dielectric constant, and P-E hysteresis loop measurements.

Effect of La Doping on the Dielectric and the Ferroelectric Properties of Lead-Free Na1/2Bi1/2TiO3 (NBT) Ferroelectric Ceramics

김진수,Saes Byul Kim,최병춘,정중현,Young Woo No,Su Tae Chung,Se Mo Son 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.2

To investigate the effect of La-ion doping, we prepared pure Na1/2Bi1/2TiO3 (NBT) and La-doped Na1/2Bi1/2-xLaxTiO3 (NBLT) ceramics by using a solid-state reaction method. Crystallized NBT and NBLT single-phases were confirmed by using X-ray diffraction. The La doping influenced the dielectric behavior and the ferroelectric properties. With increasing La doping, the dielectric peak broadened. The ferroelectric P-E hysteresis loop changed from a leaky shape to a slim shape. The remanent polarization slightly decreased; however, the coercive electric field decreased remarkably. In this work, the La-doping effects on the dielectric and the ferroelectric properties of lead-free NBT ferroelectric ceramics were investigated by using X-ray diffraction, dielectric constant and ferroelectric P-E hysteresis loop measurements.