Papers by Keyword: Bismuth Titanate

Paper TitlePage

Authors: Jun Jie Hao, Xiao Hui Wang, Jian Ling Zhao, Long Tu Li
Abstract: Textured bismuth titanate ceramics were successfully produced by spark plasma sintering, using plate-like Bi4Ti3O12 particles prepared by a molten salt method. The microstructure and electric properties of the samples were investigated. The results show that the textured Bi4Ti3O12 ceramics electric property is anisotropic in different direction, and spark plasma sintering is an effective sintering technology to get textured dense Bi4Ti3O12 ceramics at a low temperature.
1133
Authors: Glauber Márcio da Silva Luz, Maria Virginia Gelfuso, Daniel Thomazini, Pedro Perri Pinto, Antônio José Faria Bombard
Abstract: Electrorheological uids (ER) are commonly known as suspensions composed of semiconducting particles dispersed in insulating oil that respond to electric fields by gelling. The increase in suspension viscosity on application of the field is typically rapid and reversible and as a result, the ER response is amenable to applications where real time control of stress transfer properties is required. Ferroelectric particles are interesting in this application due to the presence of spontaneous polarization and high dielectric constant. Particularly, Bismuth Titanate (Bi4Ti3O12 - BIT) is well-known as layer-structured ferroelectrics, so the typical morphology of these crystals is lamellar. Therefore, these particles dispersed in oil, in the presence of an electric field must produce an interesting ER response. Thus, BIT powders were prepared by the conventional solid state reaction method and the particles size was adjusted using ball milling process. Different ER fluids containing average particles size about 2.5 to 0.5 μm were dispersed in silicon oil about 10% vol and were submitted to AC and DC electric field. The relation between the BIT particles size with the ER response was observed, presenting an increase of the shear stress with the reduction on particle size.
1462
Authors: Pusit Pookmanee, Sukon Phanichphant
Abstract: Bismuth titanate was prepared from the sol-gel method. Bismuth nitrate and titanium isopropoxide were used as the starting precursors with the mole ratio of Bi:Ti as 4:3. Solutions were mixed in acetic acid medium and heat at 80 oC for 2h. Sols were obtained after adjusting the final of pH of solution to 2. Gels were formed after drying at 100 oC for 24h. The milled powders were calcined at 500-800 oC for 2h. The phase formation was investigated by X-ray diffractometry (XRD). Single phase with orthorhombic structure of bismuth titanate was obtained after calcination at 700 oC for 2h. The morphology and chemical composition were studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The average particle size was 0.50- 1.5 μm with the irregular shape. The elemental composition of bismuth, titanium and oxygen showed the characteristic X-ray energy values.
247
Authors: C.Q. Huang, X.B. Liu, X.A. Mei, J. Liu
Abstract: The electrical properties of Er2O3-doped bismuth titanate,Bi4-xErxTi3O12 (BET) ceramics prepared by a conventional electroceramic technique were investigated. XRD analyses revealed Bi-layered perovskite structure in all samples. SEM micrographs showed randomly oriented and plate-like morphology. For the samples with x=0.4 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-E hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.6 and 0.8 the current-voltage characteristics showed simple ohmic behaviors and their P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BET ceramic with x=0.8 were above 20μC/cm2 and 65KV/cm , respectively.
162
Authors: Yi Bing Cheng, Qun Bao Yang, Yan Mei Kan, Pei Ling Wang, Yong Xiang Li, Qing Rui Yin, Dong Shen Yan
371
Authors: Yuuki Kitanaka, Yuji Noguchi, Masaru Miyayama
Abstract: Polarization switching and domain dynamics in unpoled and poled crystals of bismuth titanate by applying electric field along the crystallographic c axis were investigated through polarization measurements and domain observations by optical microscope and piezoelectric force microscope. Poled crystals showed a well-saturated polarization hysteresis with a remanent polarization of 4.4 μC/cm2 and a coercive field of 4.7 kV/cm. Domain observations reveal that lenticular domain acts as an initial nucleus during polarization switching. The sidewise motion of the lenticular-domain walls and resultant single domain state were easily established for the poled crystals, while the lenticular domains observed in unpoled crystals were clamped even though a high electric field was applied to them.
69
Authors: Nina Pavlovic, Dragan Rajnovic, L. Sidjanin, Vladimir V. Srdic
Abstract: Cerium- and lanthanum- substituted bismuth titanate (Bi4-xAxTi3O12; where A=La or Ce, and x=0, 0.5 and 1) ceramics were prepared from nanopowders synthesized by coprecipitation method. The as-synthesized powders were calcined, uniaxially pressed and finally sintered at 1050°C. It was shown that sintering behaviour, phase composition and grain morphology of the obtained ceramics were influenced by the presence of lanthanum and especially cerium ions in the titanate structure. Mechanical properties (hardness and fracture toughness) were measured at room temperature on polished sample surfaces using a Vickers microhardness tester. The hardness values for of bismuth titanate based ceramics were in the range for some other important perovskite titanate, whereas their fracture toughness was somewhat higher.
330
Authors: X.A. Mei, M. Chen, J. Liu, R.F. Liu
Abstract: The electrical properties of Gd-doped bismuth titanate Bi4-xGdxTi3O12 (BGT) ceramics prepared by a conventional electroceramic technique were investigated. XRD analyses revealed Bi-layered perovskite structure in all samples. SEM micrographs showed randomly oriented and plate-like morphology. For the ceramics with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-E hysteresis loops were characterized by large leakage current, whereas for the ceramics with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BGT ceramic with x=0.8 were above 16μC/cm2 and 70KV/cm , respectively.
261
Authors: Umar Al Amani Azlan, Ahmad Fauzi Mohd Noor, Yusliza Yusuf, Nooririnah Omar, Noraiham Mohamad
Abstract: This paper reported the doping effect on BIT by two different rare-earth compounds i.e. Nd and Sm, each at different mole content (0.25, 0.5, 0.75 and 1.0 mol). The so-called single-step combustion synthesis was used to produce the as-combusted powders, whereby the intermediate calcination step was then eliminated. This method was able to sinter the samples at temperature as low as 1000°C for 3 h. The entire ceramics were characterized for phase detection and stability, microstructure and dielectric properties. It was found that the single phase BIT was successfully formed with Nd and Sm doping. However, little content of pyrochlore phase was detected in the sample with Sm doping particularly at high mole content. (0.5 to 1.0 mol). Besides, a remarkable decrease in the grain size with better microstructure was observed particularly at high mole content (1.0). The improvement in microstructure led to the increase in dielectric constant with low dielectric loss.
397
Authors: Yan Zou, Qiu Xiang Liu, Yan Ping Jiang, Xin Gui Tang
Abstract: Bi3.4Nd0.6Ti3O12 (BNT) thin films have been prepared on Si (100) substrate by RF magnetron sputtering method. The crystalline structures were studied by X-ray diffraction. The surface of the films have been observed by SEM. The reflectivity was measured by n & k Analyzer 2000 with the wavelength from 190 to 900 nm. The optical constant, thickness and the forbidden band gap were fitted. The results showed that with the annealing temperatures raised from 600 to 750 °C, the reflectivity index decreased from 2.224 to 2.039, and the forbidden band gap decreased from 3.19 to 2.99 eV. The possible mechanism of the effect of annealing temperature on the optical properties was discussed.
620
Showing 1 to 10 of 70 Paper Titles