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Synthesis of Niobium-oxide Nano-materials and Investigation of Their Properties

Author: ZhangMiChao
Tutor: HuChenGuo
School: Chongqing University
Course: Materials Physics and Chemistry
Keywords: CHM Law The terbium doped with niobium oxide Photoluminescence Barium niobate Humidity Sensing
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 168
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Abstract


As an important oxide materials, niobium oxide (Nb2O5) has been widely used in the electronics industry, ceramic materials, photocatalytic, optical glass and aerospace industry. Recent years, with the rapid development of new materials and nanotechnology, functional ceramic based on the nanoscale the Nb2O5 related material in more and more widespread. Therefore, based on the preparation, properties, and applications of oxide nanomaterials research has become an urgent need to study the subject. This article studies the Nb2O5: Tb3, and BaNbO3 nanocrystalline nature and its preparation method. Using a low-temperature atmospheric pressure, the preparation of new methods of operation is simple, low cost, ease of industrial promotion - composite hydroxide media (Composite-Hydroxide-Mediated CHM). Terbium doped niobium oxide using this method, to prepare a novel crystalline material - nest shaped Nb2O5 is: of Tb3 microspheres. By X-ray diffraction (XRD) characterization and field emission scanning electron microscope (FE-SEM) and found that it is single-phase and monoclinic structure, the average size of 1 μm, has a unique shape of the graded nest. Nb2O5: Tb3 optical properties of terbium-doped such that the light emitting of the niobium oxide is more significant, with a 535nm excitation wavelength of the de-excitation, and found a strong emission peak intensity at 613 nm at which showed that the synthesized Nb2O5 : Tb3 samples as red phosphor may have important applications in the lighting system and optical devices. The article also discusses the composite hydroxide media prepared nanoscale (ultrafine powder with an average particle size of 1-100nm) BaNbO3 powder optimum conditions, the reaction time form BaNbO3 nanometer grain size, based on BaNbO3 nanocrystals moisture sensitive nature. By XRD, FE-SEM, TEM, and UV-Vis characterization, it is found that the uniform particles, morphology rules, an average size of 50-200nm, and the particle diameter is reduced with the extension of the growth time. Membrane electrode made of the nanoparticles with good humidity sensing properties of the electrode resistance dramatic changes with changes in humidity. Along with the relative humidity from 10% to 80%, the electrode resistance from 932.4 M? Change to 2.2 M?, When the relative humidity from 20% to 60%, response time and recovery time of 12 seconds and 32 seconds, this The results showed that the barium niobate nanoparticles in highly sensitive environmental monitoring and humidity control of electronic devices has important applications in the field. Finally, the ionic conductivity model to explain the mechanism of the humidity sensor Humidity Sensing.

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