共查询到20条相似文献,搜索用时 15 毫秒
1.
Yunfei Chang Zupei Yang Lirong Xiong Zonghuai Liu Zenglin Wang 《Journal of the American Ceramic Society》2008,91(7):2211-2216
Lead-free (K0.44 Na0.52 Li0.04 )(Nb0.80− x Ta0.20 Sb x )O3 piezoelectric ceramics were prepared by the ordinary sintering method. The much higher Pauling electronegativity of Sb compared with Nb makes the ceramics more covalent. By increasing x from 0.00 to 0.06, the phase structure of the ceramics changed from the tetragonal to the pseudocubic phase, and both the bands in the Raman scattering spectra shifted to lower frequency numbers. The grain growth of the ceramics was improved by substituting Sb5+ for Nb5+ . By increasing x , the dielectric properties were optimized and the variation of dielectric constants before and after poling became smaller. Only the tetragonal–cubic phase transition was observed above room temperature in all the ɛr – T curves. The degree of diffuseness increased from 1.29 at x =0.00 to 1.96 at x =0.06, indicating that the ceramics at x =0.06 changed to an approximate ideal relaxor ferroelectric. The temperature dependences of f r and k p became better by increasing x properly. Significantly, the ceramics with x between 0.00 and 0.04 had high density and outstanding electrical properties ( d 33 =241–272pC/N, k p =0.42–0.52, ɛr =1258–1591, tan δ=0.015–0.025, T c =280°–355°C, E c =10.62–12.60 kV/cm, and P r =16.19–20.13 μC/cm2 ). Besides, the underlying mechanism for variations of the electrical properties due to Sb5+ substitution was explained in this work. 相似文献
2.
Effects of La on Dielectric and Piezoelectric Properties of Pb1−x La2x/3 (Nb0.95 Ti0.0625 )2 O6 Ceramics
Gao-li Men Peng Liu Ruo-xi Zhang Hong Chen Bo Wang Jian-ping Zhou Gang-qiang Zhu 《Journal of the American Ceramic Society》2009,92(8):1753-1757
Ceramics with the chemical compositions of Pb1− x La2 x /3 (Nb0.95 Ti0.0625 )2 O6 (0≤ x ≤0.060) (PLTN) were prepared by the conventional solid-state reaction method. X-ray diffraction analysis indicated that Ti and La doping not only decreased the rhombohedral–tetragonal phase transformation temperature, but also stabilized the orthorhombic phase of PLTN ceramics. All ceramics sintered at 1190°–1250°C had shown the pure orthorhombic ferroelectric phase. La doping suppresses grain growth and inhibits the formation of pores and cracks, resulting in an increase in relative density up to 97%. The amount of La doping to PLTN ceramics obviously affect ceramics' piezoelectric constant ( d 33 ) and dielectric loss (tanδ). The sample with x =0.015 possesses high Curie temperature ( T c =560°C), low dielectric loss (tanδ=0.0054), and excellent piezoelectric constant ( d 33 =92 pC/N), presenting a high potential to be used in high-temperature applications as piezoelectric transducers. 相似文献
3.
Yuanyu Wang Qibin Liu Jiagang Wu Dingquan Xiao Jianguo Zhu 《Journal of the American Ceramic Society》2009,92(3):755-757
(1− x )(Na0.5 K0.5 )NbO3 – x AgSbO3 lead-free piezoelectric ceramics were prepared by normal sintering. The effects of the AgSbO3 on the phase structure and piezoelectric properties of the ceramics were systematically studied. These results show that the AgSbO3 -modified (K0.50 Na0.50 )NbO3 lead-free piezoelectric ceramics form stable solution with orthorhombic structure, and the Curie temperature and the polymorphic phase transition of the ceramics decreased with increasing AgSbO3 . The result shows that the piezoelectric properties of the ceramics strongly depend on the AgSbO3 . The ceramics with x =0.05 possess optimum properties ( d 33 =192 pC/N, k p =43%, T c =348°C, T o−t =145°C, ɛr ∼632, and tan δ∼3.5%). These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics. 相似文献
4.
Lead-free (Na0.52 K0.48− x )(Nb1− x − y Sb y )O3 - x LiTaO3 (NKNS–LT) piezoelectric ceramics have been fabricated by ordinary sintering. A special attention was paid to the composition design through which the dielectric and piezoelectric properties of the (Li, Ta, Sb) modified NKN systems were significantly promoted. A property spectrum was generated with a particular discussion on the relationship between the Sb content, the LT content, the polymorphic phase transition, and the electrical properties and their temperature stability. Excellent and tunable electrical properties of d 33 =242–400 pC/N, k p =36%–54%, , and T c =230°–430°C demonstrate a tremendous potential of the compositions studied for device applications. 相似文献
5.
Jiagang Wu Ting Peng Yuanyu Wang Dingquan Xiao Jumu Zhu Yong Jin Jianguo Zhu Ping Yu Lang Wu Yihang Jiang 《Journal of the American Ceramic Society》2008,91(1):319-321
(1− x )(K0.48 Na0.52 )(Nb0.95 Ta0.05 )O3 – x LiSbO3 [(1− x )KNNT− x LS] lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was identified in the composition range of 0.03< x <0.05. The ceramics near the MPB exhibit a strong compositional dependence and enhanced electrical properties. The (1− x )KNNT– x LS ( x =0.04) ceramics exhibit good electrical properties ( d 33 =250 pC/N, k p =45.1%, k t =46.3%, T c =348°C, T o − t =74°C, P r =25.9 μC/cm2 , E c =10.7 kV/cm, ɛr ∼1352, tan δ∼3%). These results show that (1− x )KNNT– x LS ceramic is a promising lead-free piezoelectric material. 相似文献
6.
Xueyi Sun Jinxia Deng Ce Sun Jichao Li Jun Chen Ranbo Yu Guirong Liu Xianran Xing Lijie Qiao 《Journal of the American Ceramic Society》2009,92(8):1853-1855
Lead-free potassium sodium niobate-based piezoelectric ceramics (1− y )(Na0.5−0.5 x K0.5−0.5 x Li x )NbO3 − y BiScO3 ( y =0.01, x= 0–0.06) have been prepared by an ordinary sintering process. The XRD analysis showed that the structure changes from orthorhombic to tetragonal with the increase of x (at y =0.01, abbreviated as KNNBSL100 x ). At room temperature, the polymorphic phase transition from the orthorhombic to the tetragonal phase was identified at approximately 0.02≤ x ≤0.04. The piezoelectric and ferroelectric properties were significantly enhanced. The temperature dependences of the relative permittivity revealed that the Curie temperature was increased with the addition of LiNbO3 . These solid solution ceramics are promising as potential lead-free candidate materials. 相似文献
7.
Jiagang Wu Dingquan Xiao Yuanyu Wang Lang Wu Yihang Jiang Jianguo Zhu 《Journal of the American Ceramic Society》2008,91(7):2385-2387
[(K x Na1 − x )0.95 Li0.05 ](Nb0.95 Ta0.05 )O3 (K x NLNT) ( x= 0.40–0.60) lead-free piezoelectric ceramics were prepared by conventional solid-state sintering. The effects of K/Na ratio on the dielectric, piezoelectric, and ferroelectric properties of the K x NLNT ceramics were studied. The experimental results show that the electrical properties strongly depend on the K/Na ratio in the K x NLNT ceramics. The K x NLNT ( x =0.42) ceramics exhibit enhanced properties ( d 33 ∼242 pC/N, k p ∼45.7%, k t ∼47%, T c ∼432°C, T o−t =48°C, ɛr ∼1040, tanδ∼2.0%, P r ∼26.4 μC/cm2 , E c ∼10.3 kV/cm). Enhanced electrical properties of the K x NLNT ( x =0.42) ceramics could be attributed to the polymorphic phase transition near room temperature. These results show that the K x NLNT ( x =0.42) ceramic is a promising lead-free piezoelectric material. 相似文献
8.
The effect of the addition of V2 O5 on the structure, sintering and dielectric properties of M -phase (Li1+ x − y Nb1− x −3 y Ti x +4 y )O3 ceramics has been investigated. Homogeneous substitution of V5+ for Nb5+ was obtained in LiNb0.6(1− x ) V0.6 x Ti0.5 O3 for x ≤ 0.02. The addition of V2 O5 led to a large reduction in the sintering temperature and samples with x = 0.02 could be fully densified at 900°C. The substitution of vanadia had a relatively minor adverse effect on the microwave dielectric properties of the M -phase system and the x = 0.02 ceramics had [alt epsilon]r = 66, Q × f = 3800 at 5.6 GHz, and τf = 11 ppm/°C. Preliminary investigations suggest that silver metallization does not diffuse into the V2 O5 -doped M -phase ceramics at 900°C, making these materials potential candidates for low-temperature cofired ceramic (LTCC) applications. 相似文献
9.
Ruzhong Zuo Xusheng Fang Chun Ye Longtu Li 《Journal of the American Ceramic Society》2007,90(8):2424-2428
(1− x )(Na0.5 K0.5 )NbO3 –(Bi0.5 K0.5 )TiO3 solid solution ceramics were successfully fabricated, exhibiting a continuous phase transition with changing x at room temperature from orthorhombic, to tetragonal, to cubic, and finally to tetragonal symmetries. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal ferroelectric phases was found at 2–3 mol% (Bi0.5 K0.5 )TiO3 (BKT), which brings about enhanced piezoelectric and electromechanical properties of piezoelectric constant d 33 =192 pC/N and planar electromechanical coupling coefficient k p =45%. The MPB composition has a Curie temperature of 370°–380°C, comparable with that of the widely used PZT materials. These results demonstrate that this system is a promising lead-free piezoelectric candidate material. 相似文献
10.
Yuanyu Wang Jiagang Wu Dingquan Xiao Wenjuan Wu Bing Zhang Lang Wu Jianguo Zhu 《Journal of the American Ceramic Society》2008,91(8):2772-2775
[(K0.50 Na0.50 )0.95− x Li0.05 Ag x ](Nb0.95 Ta0.05 )O3 (KNLNANT- x ) lead-free piezoelectric ceramics were prepared by normal sintering. Effects of the Ag content on the microstructure and electrical properties of KNLNANT- x ceramics were systematically investigated. It is found that the ceramics with x =0.03 exhibit relatively good electrical properties along with high Curie temperature: ( d 33 ∼252 pC/N, T c ∼438°C, k p ∼45.4%, P r ∼30.1 μC/cm2 , E c ∼13.8 kV/cm, ɛr ∼1030, and tan δ∼2.6%). The related mechanism for enhanced electrical properties of the ceramics was also discussed. These results show that KNLNANT-0.03 ceramic is a promising candidate material for high temperature lead-free piezoelectric ceramics. 相似文献
11.
Lead-based ferroelectric (FE) ceramics exhibit superior electromechanical properties; therefore, there has been an increased focus on developing new lead-based FE materials with high Curie temperature ( T c ) and enhanced properties. The aim of this study was to investigate new compositions in the Pb(Mg1/3 Nb2/3 )O3 –Pb(Yb1/2 Nb1/2 )O3 –PbTiO3 ( PMN–PYbN–PT) system to enhance the electromechanical properties while increasing the T c and lowering the sintering temperature. The 0.575[0.5PMN–0.5PYbN]–0.425PT composition at PMN/PYbN (50/50) mole ratio were prepared by reactive sintering PMNT and PYbNT powder mixtures at 950°–1200°C for 4 h. PMNT and PYbNT powders were calcined via the columbite method. Samples were prepared by cold isostatic pressing at 80 MPa. Dense and fully perovskite 0.575[0.5PMN–0.5PYbN]–0.425PT ceramics were fabricated at 975°C for 4 h, and these samples displayed a remnant polarization ( P r ) of 32 μ C/cm2 , coercive field ( E c ) of 17 kV/cm, and a piezoelectric charge coefficient ( d 33 ) of 475 pC/N. It is proposed that this ternary system can be tailored for various applications. 相似文献
12.
Atsushi Yokoi Junji Sugishita Akinori Kan Hirotaka Ogawa 《Journal of the American Ceramic Society》2008,91(1):160-163
The effects of V substitution for Nb on the dielectric and polarization properties of Sr0.5 Bi2.25 Na1.25 (Nb3− x V x )O12 ceramics were investigated in this study. From the X-ray powder diffraction results, no secondary phase was detected in the composition range of 0–0.075. The remanent polarizations ( P r ) of the samples in the composition range of 0–0.03 were improved by the V substitution for Nb and the highest P r value of approximately 15 μC/cm2 was obtained at x =0.03; it was noted that the V substitution for Nb was effective in improving the P r values in this ceramics. On the other hand, the coercive fields ( E c ) of the samples were on the order of approximately 40 kV/cm in such a composition range. Moreover, the anomalous variations in the dielectric constant were observed in the composition range of 0–0.075. Also, it was observed that the dielectric loss increased drastically at the temperature of approximately 500°C. 相似文献
13.
Qiyi Yin Shuoguo Yuan Qiang Dong Changan Tian 《Journal of the American Ceramic Society》2010,93(1):167-170
A new type (1− x )(K0.485 Na0.485 Li0.03 )NbO3 – x Pb(Zr0.53 Ti0.47 )O3 piezoelectric ceramics was fabricated by conventional ceramics sintering technique. Their microstructure and electrical properties of the ceramics were also studied. X-ray diffraction and scanning electron microscopy patterns indicate that all ceramics samples exhibit a pure perovskite and highly dense structure, and the coexistence of the tetragonal and orthorhombic phases is formed; The ceramic with x =0.75 exhibits the following excellent properties: d 33 =363 pC/N, k p =63%, Q m =142, ɛr =1590, tan δ=1.70%, P r =28.6 μC/cm2 , E c =0.89 kV/mm, T c =295°C. These results indicate that the ceramic is a promising candidate for piezoelectric ceramics in practical applications. 相似文献
14.
Xueyi Sun Jun Chen Ranbo Yu Ce Sun Guirong Liu Xianran Xing Lijie Qiao 《Journal of the American Ceramic Society》2009,92(1):130-132
Lead-free potassium sodium niobate-based piezoelectric ceramics (1− x )(Na0.5 K0.5 )NbO3 – x BiScO3 (KNN–BS) ( x =0∼0.05) have been prepared by an ordinary sintering process. Single perovskite phase of KNN–BS exhibits an orthorhombic symmetry at x <0.015 and pseudocubic symmetry at x >0.02, separating by a MPB at 0.015≤ x ≤0.02. Piezoelectric and ferroelectric properties are significantly enhanced in the MPB, which are as follows: piezoelectric constant d 33 =203 pC/N, planar coupling coefficient k p =0.36, remnant polarization P r =24.4 μC/cm2 . These solid solution ceramics look promising as a potential lead-free candidate materials. 相似文献
15.
Fei Zhao Zhenxing Yue Jing Pei Hao Zhuang Zhilun Gui Longtu Li 《Journal of the American Ceramic Society》2007,90(8):2461-2466
Microwave dielectric ceramics with the composition of Ba[Ti1− x (Ni1/2 W1/2 ) x ]O3 ( x =0.4–0.6) were prepared by a solid-state reaction method. The evolution of the crystalline phases was investigated by X-ray powder diffraction analysis. A cubic-to-hexagonal phase transition occurred between 1000° and 1300°C. The phase transition is irreversible; thus, the hexagonal phase remains stable at room temperature. The X-ray powder diffraction data for x =0.5 were refined using the Rietveld method. It was identified as a h -BaTiO3 -type hexagonal perovksite with the space group of P 63 / mmc . It also reveals that random occupancy of Ti4+ and W6+ ions occurs in the B-site substructures, whereas Ni2+ ions exclusively occupy the octahedral site in the corner-sharing octahedron. The dielectric properties of dense-sintered ceramics were characterized at microwave frequencies. With an increase in x from 0.4 to 0.6, the Q × f value increased from 26 700 to 42 000 GHz, whereas ɛr decreased from 29.8 to 20.0, and τf from +6.5 to −9.9 ppm/°C. 相似文献
16.
Sergey Kucheiko Dong-Hun Yeo Ji-Won Choi Seok-Jin Yoon Hyun-Jai Kim 《Journal of the American Ceramic Society》2002,85(5):1327-1329
The microwave dielectric properties of CaTi1− x (Al1/2 Nb1/2 ) x O3 solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO3 . The substitution of Ti4+ by Al3+ /Nb5+ improved the quality factor Q of the sintered specimens. A small addition of Li3 NbO4 (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛr ) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τf ) of −2 ppm/K. Li3 NbO4 as a sintering additive had no harmful influence on τf of ceramics. 相似文献
17.
Hongliang Du Daijun Liu Fusheng Tang Dongmei Zhu Wancheng Zhou Shaobo Qu 《Journal of the American Ceramic Society》2007,90(9):2824-2829
Lead-free piezoelectric (K0.5 Na0.5 )NbO3 – x wt% Bi2 O3 ceramics have been synthesized by an ordinary sintering technique. The addition of Bi2 O3 increases the melting point of the system and improves the sintering temperature of (K0.5 Na0.5 )NbO3 ceramics. All samples show a pure perovskite phase with a typical orthorhombic symmetry when the Bi2 O3 content <0.7 wt%. The phase transition temperature of orthorhombic–tetragonal ( T O − T ) and tetragonal–cubic ( T C ) slightly decreased when a small amount of Bi2 O3 was added. The remnant polarization P r increased and the coercive field E c decreased with increasing addition of Bi2 O3 . The piezoelectric properties of (K0.5 Na0.5 )NbO3 ceramics increased when a small amount of Bi2 O3 was added. The optimum piezoelectric properties are d 33 =140 pC/N, k p =0.46, Q m =167, and T C =410°C for (K0.5 Na0.5 )NbO3 –0.5 wt% Bi2 O3 ceramics. 相似文献
18.
Yudong Hou Mankang Zhu Feng Gao Hao Wang Bo Wang Hui Yan Changsheng Tian 《Journal of the American Ceramic Society》2004,87(5):847-850
Pb(Zn1/3 Nb2/3 )0.20 (Zr0.50 Ti0.50 )0.80 O3 ceramics of pure perovskite structure were prepared by the two-stage method with the addition of 0–3.0 wt% MnO2 and their piezoelectric properties were investigated systematically. The MnO2 addition influences in a pronounced way both the crystal structure and the microstructure of the materials. The materials are transformed from the tetragonal to the rhombohedral structure, and the grain size is enhanced when manganese cations are added. The distortion of crystal structure for samples with MnO2 addition can be explained by the Jahn–Teller effect. The values of electromechanical coupling factor ( k p ) and dielectric loss (tan δ) are optimized for 0.5-wt%-MnO2 -doped samples ( k p = 0.60, tan δ= 0.2%) and the mechanical quality factor ( Q m ) is maximized for 1.0-wt%-MnO2 -doped samples ( Q m = 1041), which suggests that oxygen vacancies formed by substituting Mn3+ and Mn2+ ions for B-site ions (e.g., Ti4+ and Zr4+ ions) in the perovskite structure partially inhibited polarization reversal in the ferroelectrics. The ceramics with 0.50–1.0 wt% MnO2 addition show great promise as practical materials for piezoelectric applications. 相似文献
19.
Ki Hyun Yoon Hong Kyu Lee Hong Ryul Lee 《Journal of the American Ceramic Society》2002,85(11):2753-2758
The electromechanical and electric-field-induced strain properties of x Pb(Yb1/2 Nb1/2 )O3 · y PbZrO3 ·(1− x − y )PbTiO3 ( x = 0.12, 0.25, 0.37; y = 0.10–0.40) ceramics have been studied systematically as a function of Pb(Yb1/2 Nb1/2 )O3 (PYN) content and PbZrO3 /PbTiO3 (PZ/PT) ratio. In addition, the effect of MnO2 on the electromechanical properties of 0.12Pb(Yb1/2 Nb1/2 )O3 ·0.40PbZrO3 ·0.48PbTiO3 was also investigated. The maximum transverse strain values of 1.6 × 10−3 for x = 0.12, 1.45 × 10−3 for x = 0.25, and 1.36 × 10−3 for x = 0.37 were obtained at the compositions which were regarded as the morphotropic phase boundary (MPB). The transverse strain was maximized at the MPB composition. The value of the maximum electromechanical coupling coefficient was 0.69 for y = 0.40 and x = 0.12 composition. In the 0.12Pb(Yb1/2 Nb1/2 )O3 ·0.40PbZrO3 ·0.48PbTiO3 composition, the temperature of the maximum dielectric constant decreased and the grain size increased with an addition of MnO2 . The electromechanical coupling coefficient decreased while the mechanical quality factor rapidly increased with an addition of MnO2 . These resulted mainly from the acceptor effect of manganese ions that were produced by doping MnO2 into the perovskite structure. 相似文献
20.
Takashi Wakasugi Rikuo Ota Jiro Fukunaga 《Journal of the American Ceramic Society》1992,75(11):3129-3132
In order to evaluate the crystallization tendency of glasses, the ratio of the crystallization temperature to the liquidus temperature ( T c / T L ) was obtained by DTA measurement for the Na2 O–B2 O3 and Na2 O–B2 O3 –Al2 O3 systems. The critical cooling rate for glass formation ( Q *) was also measured. The measurements were performed in the composition range of (100 − x )Na2 O–( x )B2 O3 , ( x = 25–35 and 60–100 mol%), and (100 − y )0.5Na2 O·0.5B2 O3 −( y )Al2 O3 , ( y = 6–34 mol%). The relationship between T c / T L and Q * was discussed. A linear relationship between T c / T L and log Q * for these systems was found. Furthermore, the relationship between T c / T L and Q * was verified by computer simulation based on the crystallization kinetics of glass or supercooled liquid. 相似文献