19132-56-0Relevant academic research and scientific papers
Fabrication of flexible energy harvesting device based on K0.5Na0.5NbO3 nanopowders
Zhuang, Yongyong,Xu, Zhuo,Li, Fei,Liao, Zhipeng,Liu, Weihua
, p. 113 - 117 (2015)
K0.5Na0.5NbO3 (KNN) powder was synthesized by a novel sol-gel method and used to fabricate an energy harvesting device. The precursor gel and KNN powder were studied by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The elemental composition of the KNN powder was characterized by energy dispersive X-ray analysis (EDAX). Well crystallized single phase perovskite KNN powder with an average particle size on the order of 450 nm was obtained from the gel after calcining at 750 °C for 2 h. A flexible and implantable energy harvesting device fabricated using the KNN nanopowder exhibited an output power of up to 0.13 μW with a load resistance of 100 MΩ. The Young's modulus of the device was determined to be 10.4 GPa by atomic force microscopy (AFM).
Properties of ultrafine-grained Na0.5K0.5NbO 3 ceramics prepared from nanopowder
Fang, Jian,Wang, Xiaohui,Li, Longtu
, p. 1654 - 1656 (2011)
In this paper, highly pure Na0.5K0.5NbO3 nanopowder was prepared from an economical sol-gel method. Using the nanopowder, dense Na0.5K0.5NbO3 ceramics with ultrafine grain sizes in the range of 200-600 nm were fabricated successfully by low-temperature solid-state sintering at 1085°C for 4 h. The ultrafine-grained ceramics exhibited fine ferroelectric, piezoelectric, and dielectric characteristics. Its room temperature d33, Kp, ε33T/ε0 at 1 kHz, tan δ and relative density are 154 pC/N, 30.5%, 407%, 0.0155%, and 96.8%, respectively. The results indicate that it is considerably potential to synthesize ultrafine-grained doped potassium-sodium niobate ceramics with excellent properties by using of nanopowder prepared from the sol-gel method.
Cation exchange in oxohydroxide matrices of niobium(V)
Ivanenko,Udalova,Lokshin,Kalinnikov
, p. 193 - 198 (2001)
Exchange of lithium, sodium, and potassium cations for hydrogen ions in oxohydroxide matrices of niobium(V), with alkali metal to niobium ratio of 1, was studied potentiometricaly. The possibility is considered of predicting the content of various singly charged cations in the case of their simultaneous presence in a complex hydrated oxide based on niobium(V).
Luminescence of Eu-doped langanite nanopowders synthesized by a citrate sol-gel method
Georgescu,Voiculescu,Toma,Nastase,Matei,Osiac
, p. 470 - 474 (2010)
Eu-doped langanite nanopowders were prepared by a citrate sol-gel method and annealed in air at various temperatures between 700 °C and 1000 °C. For annealing temperatures up to 800 °C, only the langanite phase is observed. For higher annealing temperatur
Synthesis and characterization of nanoporous Bi3NbO7 films: Application to photoelectrochemical water splitting
Jiang, Jiangang,Wang, Meng,Chen, Qingyun,Shen, Shaohua,Li, Mingtao,Guo, Liejin
, p. 10542 - 10548 (2014)
Nanostructured Bi3NbO7 films were successfully prepared via an ultrasonic spray pyrolysis method by using Bi(NO 3)3·5H2O and Nb2O5 as precursors. The as-prepared films were systematically characterized by X-ray diffraction, Atomic Force Microscopy (AFM), field emission scanning electron microscopy (FESEM), UV-vis absorption spectra and X-ray photoelectron spectroscopy. The characterization results revealed that the nanostructured Bi3NbO7 possessed a cubic structure, nanoporous morphology and a visible light absorption with an optical band gap of about 2.8 eV. Moreover, electrochemical and photoelectrochemical measurements were carried out and a maximum photocurrent density of 2.8 μA cm-2 at the potential of 0.7 V vs. SCE was obtained for the Bi3NbO7 film deposited at 350 °C. The improvement of the film photoelectrochemical properties was contributed by novel nanoporous morphology that supply sufficient electrode-solution contact area. By addition of methanol into the solution, the photocurrent increased by 60%. The photoelectrochemical results reveal that the prepared films have the potential for hydrogen production via splitting water.
Citrate sol-gel method to prepare nanoparticles of a piezoelectric crystal material: La3Nb0.5Ga5.5O14 at low temperature
Yu,Yuan,Duan,Kong,Shi,Guo,Wang,Cheng,Wang
, p. L1-L4 (2008)
The nanoparticles of a piezoelectric crystal material: La3Nb0.5Ga5.5O14 (LGN) have been prepared via a citrate sol-gel method, the process of which was simple and the crystallization temperature of LGN nanoparticles was low. The sintered samples were characterized by means of thermogravimetry/differential thermal analysis (TG/DTA), X-ray powder diffraction (XRPD), Fourier transform infrared (FT-IR) spectra, transmission electron microscope (TEM) and high-resolution transmission electron micrography (HRTEM). All the results illustrate that the trigonal crystallographic phase LGN nanoparticles were well crystallized. It is significant to the LGN crystal growth, as in which, the problem of decompensate and evaporate of Ga2O3 at high temperatures may be resolved.
Crystal structures, phase stability, and dielectric properties of (1-x) Bi3/2MgNb3/2O7-x Bi2Zn 2/3Nb4/3O7 ceramics
Dong,Li,Jin,Yu,Xu
, p. 433 - 439 (2014)
The preparation, crystal structures, phase stability and dielectric properties of the (1-x) Bi3/2MgNb3/2O7-x Bi2Zn2/3Nb4/3O7 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) ceramics were investigated systematically. The sol-gel process was employed to produce crystalline, single-phase Bi1.5Mg 1.0Nb1.5O7 (BMN) and Bi2(Zn 2/3Nb4/3)O7 (β-BZN) pre-nanopowders for the synthesis of the ceramics. X-ray diffraction data indicated that these ceramics presented a phase transition for Bi3+ and Zn 2+-rich specimens (x ≥ 0.6), from cubic pyrochlore to orthorhombic zirconolite-like structure. The tolerance factor (t) combined with r A/rB value and the lattice energy (U) were employed to provide an indication of the structural stability of the (1-x) BMN-x β-BZN cubic pyrochlores (x ≤ 0.4). The tolerance factor (t) calculation contain more structural information, which gives further insight into the details of the structural stability features in the (1-x) BMN-x β-BZN cubic pyrochlores. The relationships between the crystal structures and dielectric properties of the ceramics were determined, and the dielectric loss was related to the phase stability of the system. It is suggested that the dielectric properties are mainly determined by the phase structure, composition and stability in the (1-x) BMN-x β-BZN system.
Production of nanoscale Ba(Zn1/3Nb2/3)O3 microwave dielectric ceramics by polymerised complex method
Sert, Duygu,Mergen, Ayhan
, p. 396 - 399 (2009)
Ba(Zn1/3Nb2/3)O3 nanoparticles have been synthesized by a polymerised complex method by using precursor materials of barium nitrate, zinc acetate, niobium oxide, hydrofluoric acid and citric acid. Thermal decomposition cha
Sol-gel derived (Li, Ta, Sb) modified sodium potassium niobate ceramics: Processing and piezoelectric properties
Wang, Hongqiang,Zuo, Ruzhong,Fu, Jian,Liu, Yi
, p. 936 - 941 (2011)
Nano-scaled lead-free perovskite powders (50-100 nm) with a composition of (Na0.52K0.4425)(Nb0.8825Sb0.08) O3-0.0375LiTaO3 (NKNS-3.75LT) have been synthesized via a modified low-cost citrate sol-gel route, in which Nb2O5 and Ta2O5 were transformed into stable and soluble chelate complexes to replace costly metal alkoxides. The thermal decomposition process and structural transformation behavior of the as-prepared xerogel was investigated by means of thermo-gravitometry and differential scanning calorimetry, X-ray diffractometry and Fourier-transform infrared spectrometry. The results indicated that the ideal crystallization of the NKNS-3.75LT powder with a single perovskite structure occurs at 500-600 °C, significantly lower than that for a conventional mixed-oxide route. Transmission electron microscopy observation showed that the crystalline powder has particle sizes in the range of 30-100 nm and exhibits polyhedron-like morphology, probably resulting in a specific grain growth behavior upon densification. The sol-gel derived NKNS-3.75LT ceramics sintered at 1090 °C exhibit excellent piezoelectric properties of d33 ～418 pC/N and kp ～0.54 for NKN based random ceramics.
Excellent stability and low dielectric loss of Ba(Fe0.5Nb0.5)O3 synthesized by a solution precipitation method
Wang, Zhuo,Wen, Yong Fei,Li, Hai Juan,Fang, Ming Rui,Wang, Chun,Pu, Yong Ping
, p. 431 - 438 (2016)
A solution precipitation method was applied to prepare Ba(Fe0.5Nb0.5)O3 powders. Nano-size BFN powders with uniform particles size (～40 nm) were synthesized by solution precipitation method, which is beneficial to calcine at low temperature (1223 K). The sintering sample with dense microstructure and uniform grain size (15 μm) was obtained at 1673 K, which exhibits enhanced dielectric properties. The dielectric loss of BFN ceramic could be significantly reduced by solution precipitation method. The frequency and temperature stability of BFN ceramics could also be improved. The complex impedance spectroscopy analysis results suggested that the obtained Ba(Fe0.5Nb0.5)O3 ceramics, consisting of semiconducting grains and insulating grain boundaries, were electrically heterogeneous. The grain boundary effect was responsible for such a high value of dielectric constant.
