共查询到20条相似文献,搜索用时 15 毫秒
1.
Jong‐Hyun Kim Dae‐Hyeon Kim Tae‐Ho Lee Tae‐Gon Lee Ji‐Hyun Lee Bo‐Yun Kim Sahn Nahm Chong‐Yun Kang Jungho Ryu 《Journal of the American Ceramic Society》2016,99(12):4031-4038
K(Nb1?xMnx)O3 (KN1?xMx) ceramics with 0.005 ≤ x ≤ 0.015 were sintered at 1020°C through a normal sintering process without the formation of a liquid phase. They exhibited double polarization versus electric field (P–E) hysteresis and sprout‐shaped strain versus electric field (S–E) curves owing to the presence of a defect dipole (PD), which was formed between the acceptor Mn3+ ion and the oxygen vacancy. Moreover, the aging process was not required to develop the PD. The KN1?xMx ceramics exhibited a large strain of ~0.2% at 6.0 kV/mm. For the KN0.985M0.015 ceramic, this large strain was maintained after 104 cycles of an electric field of 6.0 kV/mm. This ceramic also maintained a double hysteresis curve at 200°C. Therefore, the KN0.985M0.015 ceramic has a large electric field‐induced strain, along with good thermal and fatigue properties for multilayer piezoelectric actuators. 相似文献
2.
Dae‐Hyeon Kim Tae‐Gon Lee Sung‐Hoon Cho Ku‐Tak Lee Chong‐Yun Kang Won‐Kyoung Lee Chung‐Kook Lee Sahn Nahm 《Journal of the American Ceramic Society》2017,100(12):5367-5373
Piezoelectric knocking sensors with a dense microstructure were fabricated at 960°C for 2 hours using various CuO‐added (Na0.5K0.5)NbO3 (NKN)‐based piezoelectric ceramics. The practical sensitivity (SP) of the knocking sensor, which is the ability to detect the knocking of a car engine, was influenced by the g33 × kp value of the piezoelectric ceramics, indicating that the g33 × kp can be considered a figure of merit of the piezoelectric ceramics used in the knocking sensor. The knocking sensor synthesized using the CuO‐added 0.95(Na0.5K0.5)(Nb0.95Sb0.05)O3–0.05CaTiO3 (CNKNS–CT) ceramic, which showed a g33 of 25.7 Vm/N and kp of 0.46, exhibited a high SP of 119 mV/g at the resonance frequency. The SP of the commercial knocking sensor, which was synthesized using the Pb(Zr,Ti)O3 (PZT)‐based ceramic, was 112 mV/g at the resonance frequency. Hence, the knocking sensor fabricated using the CNKNS–CT piezoelectric ceramic can be used to replace the commercial PZT‐based knocking sensor. 相似文献
3.
New Lead‐free (1−x)BaTiO3–xBi(Mg1/2Zr1/2)O3 Solid Solution with Morphotropic Phase Boundary and Diffuse Phase Transition 下载免费PDF全文
Shashwat Anand Rishikesh Pandey Uma Shankar Akhilesh Kumar Singh 《Journal of the American Ceramic Society》2016,99(11):3651-3658
A new lead‐free perovskite solid solution (1?x)BaTiO3–xBi(Mg1/2Zr1/2)O3 with morphotropic phase boundary (MPB) has been developed, and its structural and dielectric properties have been investigated. Rietveld structural analysis of the X‐ray diffraction data suggest a composition‐dependent tetragonal (P4mm) to cubic () phase transition with an intermediate, phase coexistence region, demarcating the MPB. The compositions with x ≤ 0.05 are tetragonal in the P4mm space group and the compositions with x ≥ 0.25 are cubic in the space group. Coexistence of monoclinic phase (space group Cm) with tetragonal/cubic phase (space group P4mm/) is observed in the MPB region for the compositions with 0.10 ≤ x ≤ 0.22. The temperature dependence of permittivity exhibits a nonrelaxor type diffuse phase transition for all the compositions across the MPB. 相似文献
4.
Piezoelectric properties of (Na0.5K0.5)(Nb1‐xSbx)O3‐SrTiO3 ceramics with tetragonal‐pseudocubic PPB structure 下载免费PDF全文
Dae‐Hyeon Kim Tae‐Gon Lee Sung‐Hoon Cho Ku‐Tak Lee Tae‐Ho Lee Youn‐Woo Hong Chang‐Hyo Hong Jeong‐Seog Kim Sahn Nahm 《Journal of the American Ceramic Society》2018,101(9):3997-4010
CuO‐added 0.96(Na0.5K0.5)(Nb1‐xSbx)O3‐0.04SrTiO3 ceramics sintered at the low temperature of 960°C for 10 hours showed dense microstructures and high relative densities. The specimens with 0.0 ≤ x ≤ 0.04 had orthorhombic‐tetragonal polymorphic phase boundary (PPB) structure. Tetragonal‐pseudocubic PPB structure was observed in specimens with 0.05 ≤ x ≤ 0.07, while the specimen with x = 0.08 has a pseudocubic structure. The structural variation in the specimens is explained by the decreases in the orthorhombic‐tetragonal transition temperature and Curie temperature with the addition of Sb5+ ions. The specimens with 0.05 ≤ x ≤ 0.07, which have tetragonal‐pseudocubic PPB structure, had large electric field‐induced strains of 0.14%‐0.016%. Moreover, these specimens also showed increased d33 values between 280 pC/N and 358 pC/N. In particular, the specimen with x = 0.055 showed particularly enhanced piezoelectric properties: d33 of 358 pC/N, kp of 0.45, and the electric field‐induced strain of 0.16% at 4.5 kV/mm. 相似文献
5.
Structural and Piezoelectric Properties of (Na1−xKx)NbO3 Platelets and Their Application for Piezoelectric Nanogenerator 下载免费PDF全文
HaiBo Xu Young‐Jin Ko Tae‐Gon Lee Su‐Jin Park Myoung‐Sub Noh Bo‐Yun Kim Jeong Seog Kim Sahn Nahm 《Journal of the American Ceramic Society》2016,99(10):3476-3484
(Na1?xKx)NbO3 (NKN) platelets synthesized at 600°C for 12 h have an Amm2 orthorhombic structure. However, the structure of NKN platelets synthesized at 500°C is a mixture of R3m rhombohedral and Amm2 orthorhombic structures. The formation of a rhombohedral structure is attributed to the presence of OH? and H2O defects in the NKN platelets. The piezoelectric strain constant (d33) of NKN platelets synthesized at 600°C for 12 h is 100 pmV?1, whereas that of NKN platelets synthesized at 500°C is lesser (50 pmV?1) due to the presence of these defects. Piezoelectric nanogenerators (PNGs) are fabricated using composites consisting of NKN platelets and polydimethylsiloxane. A large output voltage of 25 V and output current of 2.7 μA were obtained for the PNG with NKN platelets synthesized at 600°C for 6 h. This PNG shows a high output electrical energy of 3.0 μW at an external load of 5.1 MΩ. 相似文献
6.
Structure and electrical properties of perovskite layer (1−x)Sr2Nb2O7‐x(Na0.5Bi0.5)TiO3 high‐temperature piezoceramics 下载免费PDF全文
Tao Chen Ruihong Liang Yuchen Li Zhiyong Zhou Xianlin Dong 《Journal of the American Ceramic Society》2017,100(3):1065-1072
The structure and electrical properties of perovskite layer structured (PLS) (1?x)Sr2Nb2O7‐x(Na0.5Bi0.5)TiO3 (SNO‐NBT) prepared by solid‐state reaction method are investigated. The addition of NBT is beneficial to speed up mass transfer and particle rearrangement during sintering, leading to better sinterability and higher bulk density up to 96.8%. The solid solution limit x in the SNO‐NBT system is below 0.03, over which Ti4+ is preferable to aggregate and results in the generation of secondary phase. After the modification by NBT, all SNO‐NBT ceramics have a Curie temperature Tc up to over 1300°C and piezoelectric constant d33 about 1.0 pC/N. The breakthrough of piezoelectricity can mainly be attributed to rotation and distortion of oxygen octahedron as well as higher poling electric field resulting from the improved bulk density. This study not only demonstrates how to improve piezoelectricity by NBT addition, but also opens up a new direction to design PLS piezoceramics by introducing appropriate second phase. 相似文献
7.
本文采用新型溶胶-凝胶制粉技术和传统陶瓷生产工艺制备了0.93Bi0.5Na0.5TiO3-0.07Ba1-xMgxTiO3(简称BNBMT100x)体系无铅压电陶瓷,并对BNBMT陶瓷的晶相特征及其介电和压电性能进行了讨论。XRD分析表明,陶瓷样品均形成了单一的钙钛矿结构固溶体;Mg的加入对陶瓷的介电、压电性能有显著影响;陶瓷的铁电-顺电相变峰显著降低、展宽;介电损耗在室温至200℃范围内较平缓。当x=0.04时,机电耦合系数kp和kt最大,分别为16%和19%,压电常数d33值为111pC/N。 相似文献
8.
Properties of Low‐Temperature Sintering PNN–PMW–PSN–PZT Piezoelectric Ceramics with Ba(Cu1/2W1/2)O3 Sintering Aids 下载免费PDF全文
Rui Nie Qian Zhang Yang Yue Hong Liu Qiang Chen Jianguo Zhu Ping Yu Dingquan Xiao 《International Journal of Applied Ceramic Technology》2016,13(6):1119-1124
Piezoelectric ceramics Pb(Ni1/3Nb2/3)O3–Pb(Mg1/2W1/2)O3–Pb(Sb1/2Nb1/2)O3–Pb(Zr0.39Ti0.61)O3 with Ba(Cu1/2W1/2)O3 sintering aids were fabricated using economical industrial oxide powders and their piezoelectric, dielectric, and ferroelectric properties were investigated in order to develop low‐temperature sintering ceramics for multilayer piezoelectric actuators. A quadratic formula and the Curie–Weiss law reveal that the ceramics are typical displacive‐type ferroelectric relaxors. The ceramics sintered as low as 900°C have good piezoelectric properties of d33 = 551 pC/N, kp = 0.52, εr = 3583, tgδ = 0.02, and TC = 161°C, which is much promising to manufacture multilayer piezoelectric transducers. 相似文献
9.
Jie Xing Zhi Tan Lixu Xie Laiming Jiang Jing Yuan Qiang Chen Jiagang Wu Wen Zhang Dingquan Xiao Jianguo Zhu 《Journal of the American Ceramic Society》2018,101(4):1632-1645
The 0.968[(K0.48Na0.52)]Nb0.95+xSb0.05O3–0.032(Bi0.5Na0.5)ZrO3 [KNNxS–BNZ] lead‐free ceramics with nonstoichiometric niobium ion were fabricated via conventional solid‐state sintering technique and their piezoelectric, dielectric and ferroelectric properties were investigated. When x = 0.010, enhanced piezoelectric properties (d33 ≈ 421 pC/N and kp ≈ 0.47) were obtained due to the construction of rhombohendral—tetragonal phase boundary near room temperature. The KNNxS–BNZ ceramics possesses enhanced Curie temperature (Tc) with improved piezoelectric constant. A large d33 of ~421 pC/N and a high Tc ~256°C can be simultaneously induced in the ceramics with x = 0.010. Especially, good thermal stability was observed in a broad temperature range. The results indicated that our work could benefit development of KNN‐based ceramics and widen their application range. 相似文献
10.
Effects of Bi0.5Na0.5HfO3 addition on the phase structure and piezoelectric properties of (K,Na)NbO3‐based ceramics 下载免费PDF全文
Yi Chen Dandan Xue Meng Shi Xianquan Jiang Zhiqian Chen Xiaokui Liu Gang Liu Zunping Xu 《Journal of the American Ceramic Society》2017,100(9):3920-3927
Lead‐free perovskite (1‐x)(K0.48Na0.48Li0.04)Nb0.95Sb0.05O3‐x(Bi0.5Na0.5)HfO3 piezoelectric ceramics were prepared by a traditional ceramic fabrication method. An investigation was conducted to assess the effects of (Bi0.5Na0.5)HfO3 content on the crystal structure, microstructure, phase‐transition temperatures, and piezoelectric properties of the ceramics. The X‐ray diffraction results, combined with the temperature dependence of dielectric properties, revealed that the ceramics experienced a structural transition from an orthorhombic phase to a tetragonal phase with the addition of (Bi0.5Na0.5)HfO3, and a coexistence of orthorhombic and tetragonal phases was identified in the composition range of 0.005≤x≤0.015. An obviously improved piezoelectric activity was obtained for the ceramics with compositions near the orthorhombic‐tetragonal phase boundary, among which the composition x=0.005 exhibited the maximum values of piezoelectric constant d33, and planar and thickness electromechanical coupling coefficients (kp and kt) of 246 pC/N, 0.435, and 0.554, respectively. Furthermore, the Curie temperature of the ceramics was found decreasing with the increase in (Bi0.5Na0.5)HfO3 content, but still maintaining above 300°C for the phase boundary compositions. These results indicate that the ceramics are promising lead‐free candidate materials for piezoelectric applications. 相似文献
11.
Electrical Properties and Relaxor Phase Evolution of Li‐Modified BNT‐BKT‐BT Lead‐Free Ceramics 下载免费PDF全文
Ye‐Jing Dai Zhe Zhao Xiao‐Wen Zhang Si‐Hui Wang 《Journal of the American Ceramic Society》2016,99(7):2354-2360
By conventional ceramics sintering technique, the lead‐free 0.85Bi0.5Na0.5(1?x)Li0.5xTiO3‐0.11Bi0.5K0.5TiO3‐0.04BaTiO3 (x =0–0.15) piezoelectric ceramics were obtained and the effects of Li dopant on the piezoelectric, dielectric, and ferroelectric properties were studied. With increasing Li addition, the temperature‐dependent permittivity exhibited the normal ferroelectric‐to‐ergodic relaxor (FE‐to‐ER) transition temperature (TFE‐ER, abbreviated as TF‐R) decreasing down to room temperature. The increasing Li content also enhanced the diffuseness of the FE‐to‐ER transition behavior. For composition with x = 0.15, a large unipolar strain of 0.37% ( = Smax/Emax = 570 pm/V) was achieved under 6.5 kV/mm applied electric field at room temperature. Both unipolar and bipolar strain curves related to the temperature closely, and when the temperature reached the TF‐R, the normalized strain achieved a maximum value (e.g., for x = 0.10, = 755 pm/V) owing to the electric‐field‐induced ER‐to‐FE state transition. 相似文献
12.
Raz Muhammad Yaseen Iqbal Ian M Reaney 《Journal of the American Ceramic Society》2016,99(6):2089-2095
Solid solutions of (1?x)BaTiO3–xBi(Mg2/3Nb1/3)O3 (0 ≤ x ≤ 0.6) were prepared via a standard mixed‐oxide solid‐state sintering route and investigated for potential use in high‐temperature capacitor applications. Samples with 0.4 ≤ x ≤ 0.6 showed a temperature independent plateau in permittivity (εr). Optimum properties were obtained for x = 0.5 which exhibited a broad and stable relative εr ~940 ± 15% from ~25°C to 550°C with a loss tangent <0.025 from 74°C to 455°C. The resistivity of samples increased with increasing Bi(Mg2/3Nb1/3)O3 concentration. The activation energies of the bulk were observed to increase from 1.18 to 2.25 eV with an increase in x from 0 to 0.6. These ceramics exhibited excellent temperature stable dielectric properties and are promising candidates for high‐temperature multilayer ceramic capacitors for automotive applications. 相似文献
13.
Remarkable piezoelectricity and stable high‐temperature dielectric properties of quenched BiFeO3–BaTiO3 ceramics 下载免费PDF全文
Qiang Li Jianxin Wei Tinglong Tu Jinrong Cheng Jianguo Chen 《Journal of the American Ceramic Society》2017,100(12):5573-5583
Effects of quenching process on dielectric, ferroelectric, and piezoelectric properties of 0.71BiFeO3?0.29BaTiO3 ceramics with Mn modification (BF–BT?xmol%Mn) were investigated. The dielectric, ferroelectric, and piezoelectric properties of BF–BT?xmol%Mn were improved by quenching, especially to the BF–BT?0.3 mol%Mn ceramics. The dielectric loss tanδ of quenched BF–BT?0.3 mol%Mn ceramics was only 0.28 at 500°C, which was half of the slow cooling one. Meanwhile, the remnant polarization Pr of quenched BF–BT?0.3 mol%Mn ceramics increased to 21 μC/cm2. It was notable that the piezoelectric constant d33 of quenched BF–BT?0.3 mol%Mn ceramics reached up to 191 pC/N, while the TC was 530°C, showing excellent compatible properties. The BF–BT?xmol%Mn system ceramics showed to obey the Rayleigh law within suitable field regions. The Rayleigh law results indicated that the extrinsic contributions to the dielectric and piezoelectric responses of quenched BF–BT?xmol%Mn ceramics were larger than the unquenched ceramics. These results presented that the quenched BF–BT?xmol%Mn ceramics were promising candidates for high‐temperature piezoelectric devices. 相似文献
14.
Large strain response with low driving field in Bi1/2Na1/2TiO3–Bi1/2K1/2TiO3–Bi(Mg2/3Nb1/3)O3 ceramics 下载免费PDF全文
Guangzhi Dong Huiqing Fan Jing Shi Qiang Li 《Journal of the American Ceramic Society》2018,101(9):3947-3955
The (1?x)(0.8Bi1/2Na1/2TiO3–0.2Bi1/2K1/2TiO3)?xBiMg2/3Nb1/3O3 (100xBMN) ternary solid solutions were designed and prepared using a conventional solid‐state reaction. Temperature and compositional dependent ferroelectric, piezoelectric, dielectric features, and structural evolution were systematically studied. At the critical composition of 2BMN, a large bipolar strain of 0.43% was achieved at 55 kV/cm, and the normalized strain reaches to 862 pm/V at a low driving electric field of 40 kV/cm. It was found that the substitution of BiMg2/3Nb1/3O3 induces a transformation from ferroelectric to relaxor phase by disrupting the long range ferroelectric order. Therefore, as the external electric field was applied, a relaxor‐ferroelectric phase transition will be induced. This is contributed to the giant strain. The results above suggest that such a ternary composition is a promising candidate for application to actuator. 相似文献
15.
Composition and temperature dependence of structure and piezoelectricity in (1−x)(K1−yNay)NbO3‐x(Bi1/2Na1/2)ZrO3 lead‐free ceramics 下载免费PDF全文
Dawei Wang Fayaz Hussain Amir Khesro Antonio Feteira Ye Tian Quanliang Zhao Ian M. Reaney 《Journal of the American Ceramic Society》2017,100(2):627-637
Lead‐free piezoceramics with the composition (1?x)(K1?yNay)NbO3‐x(Bi1/2Na1/2)ZrO3 (KNyN‐xBNZ) were prepared using a conventional solid‐state route. X‐ray diffraction, Raman spectroscopy, and dielectric measurements as a function of temperature indicated the coexistence of rhombohedral (R) and tetragonal (T) phase, typical of a morphotropic phase boundary (MPB) as the BNZ concentration increased and by adjusting the K/Na ratio. High remnant polarization (Pr=24 μC/cm2), piezoelectric coefficient (d33=320 pC/N), effective piezocoefficient ({d_{33}^*}=420 pm/V), coupling coefficient (kp=48%), and high strain (S=0.168%) were obtained at room temperature, but significant deterioration of Pr, {d_{33}^*}, and kp were observed by increasing from room temperature to 160°C (17.5 μC/cm2, 338 pm/V, and 32%, respectively) associated with a transition to a purely T phase. Despite these compositions showing promise for room‐temperature applications, the deterioration in properties as a function of increasing temperature poses challenges for device design and remains to be resolved. 相似文献
16.
压电陶瓷PZN-PZT对压电复合材料性能的影响 总被引:1,自引:0,他引:1
本研究采用固相烧结法合成了PZN-PZT压电陶瓷粉体,并用XRD分析了其晶相组成。将PZN-PZT陶瓷粉体与PVDF复合,制备出PZN-PZT/PVDF0-3型压电复合材料,研究了陶瓷质量分数对复合材料铁电性、介电性及压电性的影响。结果表明,复合材料的铁电性、介电性和压电性能随陶瓷含量的增加而增强,当陶瓷含量为90%时,复合材料的剩余极化强度Pr达到5.27μC·cm-2,矫顽场EC为76kV·cm-1,介电常数εr为188,介电损耗tanδ为0.065,压电常数d33则达到33.4pC/N。 相似文献
17.
Improved thermal stability of the piezoelectric properties of (Li,Ag)‐co‐modified (K,Na) NbO3‐based ceramics prepared by spark plasma sintering 下载免费PDF全文
High‐performance lead‐free piezoelectric ceramics 0.94(K0.45Na0.55)1?xLix(Nb0.85Ta0.15)O3–0.06AgNbO3 (KNNLTAg‐x) were successfully prepared by spark plasma sintering technique. The doping effect of Li on the structural and electrical properties of KNNLTAg‐x (x=0, 0.02, 0.04, 0.06, 0.08 and 0.10) ceramics was studied. The lattice structure, ferroelectric and piezoelectric properties of the KNLNTAg‐x ceramics are highly dependent on the Li doping level. In particular, the Li dopant has a great impact on both Curie temperature Tc and orthorhombic‐tetragonal transition temperature TO‐T. The 4% Li‐doped sample exhibited relatively high TO‐T of 95°C, leading to a stable dynamic piezoelectric coefficient (d33*) of 220‐240 pm/V in a broad temperature range from 25°C to 105°C. Additionally, the 2% Li‐doped sample shows a high d33* of 320 pm/V at 135°C, suggesting its great potential for high‐temperature applications. 相似文献
18.
Effect of Li2O on the defect polarization in CuO‐added (K0.9Na0.1)NbO3 piezoelectric ceramics 下载免费PDF全文
Dae‐Hyeon Kim Jongseong Park Tae‐Gon Lee Sung‐Hoon Cho Su‐Jin Park Ku‐Tak Lee Jong‐Hyun Kim Sahn Nahm 《Journal of the American Ceramic Society》2017,100(11):5193-5201
CuO‐added (LixK0.9?xNa0.1)NbO3 [C(LxK0.9?xN0.1)N] ceramics with 0.0≤x≤0.05 were well‐sintered at 960°C for 6 hours. The lattice parameters of the specimens decreased with the addition of Li2O. Defect polarization (PD) formed between Cu2+ions and oxygen vacancies. Double polarization vs electric field (P‐E) hysteresis and sprout‐shaped strain vs electric field (S‐E) curves were observed in these specimens with a large strain of 0.16% at 7.0 kV/mm, possibly owing to the presence of PD. When the P‐E curve was measured at temperatures higher than 75°C, the C(K0.9N0.1)N ceramic exhibited a normal P‐E hysteresis curve, whereas the C(L0.04K0.86N0.1)N ceramic maintained the double P‐E hysteresis curve up to 125°C, indicating that Li2O increased the thermal stability of PD. The latter specimen also showed the sprout shaped S‐E curve with a strain of 0.15% at 7.0 kV/mm after 104 cycles of a high electric field of 7.0 kV/mm. 相似文献
19.
Potassium sodium niobate (KNN)‐based lead‐free piezoelectric ceramic coatings on steel structure by thermal spray method 下载免费PDF全文
Shuting Chen Chee Kiang Ivan Tan Sze Yu Tan Shifeng Guo Lei Zhang Kui Yao 《Journal of the American Ceramic Society》2018,101(12):5524-5533
For the first time, potassium sodium niobate (KNN)‐based lead‐free piezoelectric ceramic coating with strong piezoelectric response was fabricated on stainless steel substrates by thermal spray process, after introducing NiCrAlY and yttria‐stabilized zirconia (YSZ) intermediate layers. A large effective piezoelectric coefficient (d33) of 125 pm/V was obtained with the thermal‐sprayed KNN‐based ceramic coating on the steel substrates. The mechanisms of improving the structure and enhancing the properties of the KNN‐based piezoelectric ceramic coatings by introducing the intermediate layers were analyzed. Ultrasonic transducers were designed and fabricated from the KNN‐based coatings directly formed on a steel plate structure, and the feasibility for generation and detection of ultrasonic waves for structural health monitoring using the thermal‐sprayed lead‐free piezoelectric ceramic coating was demonstrated. 相似文献
20.
High‐Performance Small‐Amount Fe2O3‐Doped (K,Na)NbO3‐Based Lead‐Free Piezoceramics with Irregular Phase Evolution 下载免费PDF全文
Jinming Guo Fang Xu Xunzhong Shang Yinmei Lu Pai Li Taosheng Zhou Zaoli Zhang Yunbin He 《Journal of the American Ceramic Society》2016,99(7):2341-2346
[(K0.43Na0.57)0.94Li0.06][(Nb0.94Sb0.06)0.95Ta0.05]O3 + x mol% Fe2O3 (KNLNST + x Fe, x = 0~0.60) lead‐free piezoelectric ceramics were prepared by conventional solid‐state reaction processing. The effects of small‐amount Fe2O3 doping on the microstructure and electrical properties of the KNLNST ceramics were systematically investigated. With increasing Fe3+ content, the orthorhombic‐tetragonal polymorphic phase transition temperature (TO‐T) of KNLNST + x Fe ceramics presented an obvious “V” type variation trend, and TO‐T was successfully shifted to near room temperature without changing TC (TC = 315°C) via doping Fe2O3 around 0.25 mol%. Electrical properties were significantly enhanced due to the coexistence of both orthorhombic and tetragonal ferroelectric phases at room temperature. The ceramics doped with 0.20 mol% Fe2O3 possessed optimal piezoelectric and dielectric properties of d33 = 306 pC/N, kp = 47.0%, = 1483 and tan δ = 0.023. It was revealed that the strong internal stress in the KNLNST + x Fe ceramics with higher Fe3+ contents (x = 0.40, 0.60) stabilized the orthorhombic phase, leading to the irregular “V” type rather than the usually observed monotonic phase transition with composition change in the ceramics. 相似文献