نتایج جستجو برای: zro2
تعداد نتایج: 3340 فیلتر نتایج به سال:
Zirconium Oxide (ZrO2) is an interesting material in optical filters, gas sensors and protective coatings owing to their outstanding optical, chemical, thermal and mechanical properties. Zirconium Oxide thin films were deposited on glass substrates by sol gel dip coating method, using alcoholic solutions. The dipping solution was prepared from Zirconium OxychlorideOctahydrate and Isopropanol wi...
Throughout the Earth’s history, mass transport involved fluids. In order to address the circumstances under which Zr may have been transported in this manner, its solubility behavior in aqueous fluid with and without NaOH and SiO2 in equilibrium with crystalline ZrO2 was determined from 550 to 950 °C and 60 to 1200 MPa. The measurements were carried out in situ while the samples were at the tem...
nanocomposite of zro2/zno was prepared under ultrasonic irradiation by sol gel process from directly mixing zirconium and zinc gels. the mixture was placed under ultrasonic irradiation for 2 hours. after the aging time and filtration of the reaction mixture, the filtrated composite gel was calcinated at 500 °c for 3h in furnace. the precursor gels of zirconium and zinc were prepared from dissol...
The free energy of formation of zircon (ZrSiO4) from its oxides was determined between 1100 and 1300 K by an electrochemical method, in which values of μO2 deÞ ned by the two assemblages Fe2SiO4-Fe-SiO2 (fayalite-iron-quartz) and Fe2SiO4-Fe-ZrO2-ZrSiO4 were each measured using oxygen concentration cells with calcia-stabilized zirconia solid electrolytes. The difference in μO2 between these two ...
Transformation plasticity in ZrO2, which is responsible for the high strength and high toughness of advanced ZrO2-based ceramics, is reviewed. The tetragonal ~ monoclinic martensitic transformation is of prime importance, but its successful exploitation requires a good deal of microstructural control. Under certain conditions, the transformation can be reversible, autocatalytic, and thermoelast...
The IR spectra of bulk Nb2O5‚nH2O and niobia supported on SiO2, Al2O3, ZrO2, and TiO2 were recorded in the fundamental and overtone NbdO regions, as well as in the hydroxyl region, to develop a better understanding of the structural models of surface NbOx species. The coincidence of the IR and Raman fundamental NbdO frequency in Nb2O5/Al2O3, Nb2O5/ZrO2, and Nb2O5/TiO2 provides the strongest evi...
One-dimensional (1D) metal oxide nanomaterials, such as zinc oxide (ZnO) nanowires and nanobelts (or nanoribbons), have recently attracted immense attention due to their sizeand shape-dependent optical, mechanical, and electronic properties. In stark contrast, investigations of 1D zirconia (ZrO2) and hafnia (HfO2) nanomaterials remain unexploited largely because of the formidable challenges ass...
UV-visible diffuse reflectance spectroscopy was used to probe the electronic structure and domain size of tungsten oxide species in crystalline isopolytungstates, monoclinic WO3, and dispersed WOx species on ZrO2 surfaces. UV-visible absorption edge analysis, CO2 chemisorption, and Raman spectroscopic results show that three distinct regions of WOx coverage on ZrO2 supports appear with increasi...
The utilization of metal oxide-zeolite catalysts in the syngas-to-olefin reaction is a promising strategy for producing C2–C4 olefins from non-petroleum resources. However, effect crystal phase oxides on catalytic activity these still ambiguous. Herein, typical (ZnO/ZrO2) with different phases (monoclinic (m-ZrO2) and tetragonal (t-ZrO2)) were employed syngas conversion. (ZnO/m-ZrO2+SAPO-34) co...
The structures, processes of shrinkage, and phase composition of the compact system ZrO2-WC, obtained by hot pressing with the transmission of high current, are considered in the article. We found that as a result of compaction, the ZrO2-WC-ceramics have uniform density distribution, with the following optimal mode consolidation values T = 1,350°C, P = 30 MPa and t = 2 min. These conditions all...
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