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排序方式: 共有68条查询结果,搜索用时 31 毫秒
1.
Lingfang Zou Zhuan Li Zonglong Gao Fu Chen Wenjie Li Yong Yu Yimin Li Peng Xiao 《Ceramics International》2021,47(14):19328-19339
Improving the piezoelectric activity of lead zirconate titanate (PZT) ceramics is of great importance for practical applications. In this study, the influence of Pr3+ doping on the ferroelectric phase composition, microstructure, and electric properties on the A-site of (Pb1-1.5xPrx)(Zr0.52Ti0.48)O3 is extensively investigated. A dense and fine microstructural sample is obtained with the introduction of Pr3+. The results show that the morphotropic phase boundary (MPB) moves to the rhombohedral phase region. The rhombohedral and tetragonal phases exhibit an ideal coexistence in the 4 mol.% Pr3+ doped (PPZT4) samples. Lead vacancy and the reduction of the potential energy barrier are considered to be the key mechanisms for donor doping, which is upheld by the Pr3+ doping. Combining the I-E hysteresis loops with the P-E hysteresis loops, it becomes apparent that both contribution maximums of the domain switching and residual polarisation are in PPZT4. Moreover, the thermal aging resistance of PZT is improved by doping, and the temperature stability is optimised from 83% in PZT to 96% in PPZT4. Hence, an appropriate amount of Pr3+ doping can effectively improve the piezoelectric activity of PZT ceramics in the MPB area and optimise the performance stability of the material under application temperatures. 相似文献
2.
《Journal of the European Ceramic Society》2022,42(1):112-118
Improving piezoelectric performance is always favorable to further enhance the sensitivity and accuracy of piezoelectric devices. Here, a complex piezoelectric system of Pb(Ni1/3Nb2/3)O3-Pb(Yb1/2Nb1/2)O3-Pb(Hf0.1Ti0.9)O3 is designed and investigated in detail. Optimized piezoelectric response of ~ 880 pC/N is achieved at the composition of 0.51PNN-0.09PYN-0.40PHT. The characterization of TEM and In-situ high-energy synchrotron diffraction indicate that nanodomain growth and microdomain switching occurs in succession at around coercive electric field. Most interestingly, the coexisted tetragonal and rhombohedral-like phase transforms into multiple monoclinic-like phases with polarization vectors aligned as close to the electric field direction as possible under the strong electric field. The enhanced polarization instability in this complex morphotropic phase boundary sample should be ascribed to the strong local heterogeneity. The novel polarization rotation behavior found in this work would be important guidance for designing high-performance piezoceramics. 相似文献
3.
Effects of CeO2 doping on the structure and properties of PSN-PZN-PMS-PZT piezoelectric ceramics 总被引:1,自引:0,他引:1
SUN Qingchi LU Cuimin ZHOU Hua 《稀有金属(英文版)》2005,24(3):235-239
Quinary system piezoelectric ceramics PSN-PZN-PMS-PZT were prepared by using a two-step method. The effects of CeO2 doping on piezoelectric and dielectric properties of the system were investigated at morphotropic phase boundary (MPB). The results reveal that the relative dielectric constant ε33^T|ε0, the Curie temperature To, the piezoelectric constant d33, the mechanical quality factor Qm, and the electromechanical coupling coefficient Kp are changed with the increase of CeO2 content. On the other hand, the effects of CeO2 doping on the dielectric properties of PSN-PZN-PMS-PZT piezoelectric ceramics at high electric field are consistent with the change at weak electric field. The values of dielectric constant and dielectric loss are enhanced with the increasing of electric field. 相似文献
4.
5.
Ignacio G. del Amo David A. Pelta Juan R. González Antonio D. Masegosa 《Applied Soft Computing》2012,12(10):3176-3192
This work presents a study on the performance of several algorithms on different continuous dynamic optimization problems. Eight algorithms have been used: SORIGA (an Evolutionary Algorithm), an agents-based algorithm, the mQSO (a widely used multi-population PSO) as well as three heuristic-rule-based variations of it, and two trajectory-based cooperative strategies. The algorithms have been tested on the Moving Peaks Benchmark and the dynamic version of the Ackley, Griewank and Rastrigin functions. For each problem, a wide variety of configuration variations have been used, emphasizing the influence of dynamism, and using a full-factorial experimental design. The results give an interesting overview of the properties of the algorithms and their applicability, and provide useful hints to face new problems of this type with the best algorithmic approach. Additionally, a recently introduced methodology for comparing a high number of experimental results in a graphical way is used. 相似文献
6.
Hassakorn Wattanasarn Wattana Photankham Sakorn Inthachai Rattikorn Yimnirun Chanchana Thanachayanont 《Integrated ferroelectrics》2015,165(1):19-28
The relaxor ferroelectric materials can be found in morphotropic phase boundary (MPB) existing between tetragonal and cubic phase. Since the MPB shifts to other phases by adding ceramics composition. [(1 – x)Pb(Mg1/3 Nb2/3)O3–x Pb(Zr0.52Ti0.48)O3] were doped by 0.05Ba(Zn1/3 Nb2/3)O3 when x = 0.4, 0.3, and 0.2 ceramics, which prepared by using a two–step sintering process. The MPB transitions were studied by the use of XRD. The samples, at x = 0.4, were in MPB and then gradually shifted to cubic phase at x = 0.2. The microstructure of samples fracture found that the largest grain size of 4.51 μm for x = 0.2. This study using TEM technique which demonstrated a crystalline morphology with the largest crystal size about 1.293 μm at x = 0.3. These results also revealed that not only the ferroelectric phase shifted to relaxor behavior with decreasing PZT contents in PMN–PZT system but also activated by BZN, which led to the presence of the relaxor behavior. 相似文献
7.
Piezoelectric and ferroelectric properties of bismuth sodium titanate, (Bi1/2Na1/2)TiO3(BNT)-based solid solution, that is, (Bi1/2Na1/2)(1-x)(Pba Bab)xTiO3(a + b = 1) [BNPB(100x-100a/100b)], are studied from the viewpoint of a new group of lead-free or low-lead content piezo-electric ceramics with a rhombohedral(Fa-tetragonal (Fβ) morphotropic phase boundary (MPB). It is evident that the MPB seems to be remarkably efficacious in promoting piezoelectric and pyroelectric activities by electrical poling. X-ray diffraction data, dielectric properties and D-E hysteresis loops show that the MPB exist near (Bi1/2Na1/2)TiO3[BNT] at x = 0.13–0.14, 0.08–0.09 and 0.06–0.07 in the case of b = 0, b = 0.5 and b = 1, respectively. BNPB ceramics are superior for piezoelectric ceramics in high-frequency ultrasonic uses, or special piezoelectric actuator materials with a lower free permittivity ε33Tε0, and a high electromechanical coupling factor k33, along with a high mechanical strength. 相似文献
8.
He Qi Ruzhong Zuo Jing-feng Li Longtu Li 《Journal of the European Ceramic Society》2018,38(16):5341-5347
A morphotropic phase boundary (MPB) between rhombohedral (R) and tetragonal (T) phases was identified in a few (0.9-x)NaNbO3-0.1BaTiO3-xABO3 (x?=?0–0.05) lead-free systems. Critical roles of R-phase inducers were specially evaluated in terms of phase boundary position, microstructure and piezoelectric responses. The results indicate not only the tolerance factor of the ABO3 additive but also its ferroelectricity and corresponding volume change would influence the formation of phase boundary and further determine dielectric and ferroelectric responses. The piezoelectric coefficient d33 of MPB compositions was compared with theoretically-calculated d33-cal according to d33?=?2Pr·ε33·Q33, demonstrating that the piezoelectric response of these systems should be determined by combined effects of the phase coexistence, nano-scale domains and particularly enhanced dielectric responses. The largest d33 ~305 pC/N, the highest ε33T/εo ~2815 and the lowest Pr ~14.7 μC/cm2 were achieved in the MPB composition with 3.75% SrZrO3. These experimental results provide a valuable reference for designing new NaNbO3-based lead-free piezoelectric materials. 相似文献
9.
Karima Bounab Zelikha Necira Hayet Menasra Sofiane Ameid Abdelhak Maklid Ahmed Boutarfaia 《化学与化工:英文版》2014,(3):250-253
PMF-PZN-PZT (0.01Pb(Mol/3Fe2/3)O3-xPb(Znl/3Nb2/3)O3-(O.99-x)P(Zro53Tio 47)03 piezoelectric ceramics), where x = 0.00 0.01, 0.03, 0.05 and 0.07 were prepared by a conventional mixed-oxide method. The results show that the pure peroveskit phase forms in these ceramics. X-ray diffraction analysis indicated that the phase of the material is a MPB (morphotropic phase boundary) structure. The effects of PZN content on the crystal structure and electrical properties were investigated, optimal dielectric properties were achieved at composition x = 0.07 ceramics by calcination at 800 ℃ and sintering at 1,180 ℃, with a curie temperature of approximately 430 ℃. These results clearly show the significance of PZN in controlling the electrical responses of the PMF-PZN-PZT system. 相似文献
10.
Lumber produced from lodgepole pine logs attacked by the mountain pine beetle (MPB) infestation in British Columbia, Canada, exhibits very low initial moisture content (MC). Depending on the time elapsed since attack, the initial MC can be significantly lower than the fiber saturation point (FSP ~30%). Lumber exhibiting 19% MC or less is considered ready for the dimension lumber market and does not necessarily need to be kiln dried. However, phytosanitary regulations require that lumber products be heat treated before delivery to customers. For lumber already quite dry, the Canadian Food Inspection Agency (CFIA) kiln drying/heat treatment schedules may be too long and can result in overdrying. For the significant volume of MPB lumber with an initial MC below 19%, the use of low-pressure steam or cold water spray could allow this lumber to be heat treated without causing further drying. This approach should result in improved lumber quality because overdrying would certainly be minimized and probably eliminated. In this study, two sorts (dry and wet sort) of MPB lumber were dried in a pilot laboratory kiln humidified with low-pressure steam or cold water spray. Twelve drying runs were carried out. The experimental results indicated that the times to reach the temperature of 56°C in the core of the lumber were shortened and warp for the dry-sort lumber group was reduced when the low-pressure steam or cold water spray system was used. Thus, for MPB lumber with a low initial MC, the utilization of lower pressure steam or cold water spray during heat treatment represents an attractive alternative to reduce kiln residence time, minimize or eliminate overdrying, and improve lumber quality. 相似文献