Papers by Keyword: Yttrium

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Authors: Jian Kang, Zhi Juan Kang, Hai Yue Shan
Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of rare earth elements and yttrium (REY) in coal and associated rock samples from the Guanbanwusu Mine, Jungar Coalfield, Northern China. The Guanbanwusu coals have a similar vitrinite reflectance and sulfur content, and a slightly higher ash yield. The concentration of REY (from La to Lu plus Y) in the 6 coal of the Guanbanwusu Mine varies from 72 μg/g to 396 μg/g and averages 186 μg/g, higher than that in normal Chinese coal (136 μg/g) and much higher than that in average world hard coals. The H-type distribution patterns in the No. 6 coal (W9-2 and W9-9) were probably caused by stronger water influences than those in the other coalfield. The coal bench (W2 and W9) with L-type is because terrigenous input influence.
Authors: Jing Wei, Xin Tan, Tao Yu, Lin Zhao
Abstract: A series of Y/TiO2 nanoparticles (NPs) were synthesized via sol-gel method. The crystal structures, morphologies and chemical properties were characterized using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). We investigated the effects of different doping amounts of Y on the reaction of CO2 photoreduction. The results shown that 0.1 wt.%Y/TiO2 (0.1YT) performed the highest photocatalytic activity, which yielded 384.62 µmol/g∙cat. formaldehyde after 6 h of UV illumination.
Authors: Zhen Jiang Shen, Li Na Bing
Abstract: Colossal permittivity (CP) in BaTiO3 (BT)-based polycrystalline ceramics with normal grain sizes has been successfully obtained in yttrium (Y) doped BT ceramics (BYT) via a simple and effective method. Considering the necessary factors for CP formation mechanism, well designed doping condition and sintering procedure were carried out in the sample preparation. Characterizations show that BYT is with a pure tetragonal perovskite structure and the grain growth is depressed under the action of Y donor doping. The frequency independence of permittivity and Debye-like relaxation related to Maxwell-Wagner relaxation which occurred at the interfaces between semiconducting grains and insulating grain boundaries can be detected. These are induced by an internal barrier layer capacitance (IBLC)-type structure which formed under an overall and carefully designed synthesis procedure. But the temperature independence of permittivity does not arise because of the particular tetragonal structure and micron dimension grain sizes of BYT.
Authors: G. Kontrym-Sznajd, R.N. West, Stephen B. Dugdale
Authors: H. Sato, Mayumi Suzuki, Kouichi Maruyama, H. Oikawa
Authors: Zhen Tan, Hong Kun Wu, An Chun Mo, Zhi Qing Chen, Yu Bao Li
Abstract: The aim of this study was to evaluate the remineralizing potential of demineralized human dentin treated with Y/HA nanoparticles (doping Y with 5mol %) and HA nanoparticles suspension and whether dentin could be remineralized by HA. Human crown dentin was demineralized with EDTA for 4 hours, and then subjected to remineralization condition. The ability of these matrices to remineralize was determined by SEM, AFM and calcium levels in the remineralized tissue were measured by atomic energy spectrum analysis. The results showed that Y/HA and HA nanoparticles remineralized the demineralized dentin surface; these demineralized matrices treated with Y/HA nanoparticles remineralized to a greater extent than those treated HA nanoparticles. The differences in both the quality and quantity, as defined by Yttrium iones leading to changes in characterization of the apatite crystals might be important in effecting the ability of this tissue to remineralize. This work suggested that apatite nanoparticles caused remineralization of dentin and the yttrium ions substituted in the apatite structure might enhance their remineralization potential.
Authors: Jian Yi Cheng, Fang Xin Yu, Xue Wen Ao
Abstract: Effect of rare earth yttrium on the properties and microstructure of Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy was investigated. The results showed that Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy obtained good comprehensive performance after 80% deformation and then aging at 480°C for 1h, the hardness and electrical conductivity reached 152HV and 85.5%IACS, respectively. The aging time of Y-containing alloy for attaining peak hardness was postponed and the precipitates were finer (2-4nm) and interparticle spacing was shorter than ones of Y-free alloy. The hardness and electrical conductivity of the Y-containing alloy after 80% deformation and then aging at 480°C for 45 min reached 174HV and 82.1%IACS, respectively. The tensile fractures of the two alloys which exhibits the obvious feature of tough fracture.
Authors: Jin Xia Song, Ya Fang Han, Cheng Bo Xiao
Abstract: The effect of ion implantation of yttrium on the oxidation behavior of Ni3Al base alloy IC6 at 1100°C was investigated by SEM/EDS, TEM and XRD methods. The results indicated that after Y ion implantation, the surface of IC6 alloy changed from large column crystals to fine distributed nano-crystals, and the density of dislocations in distorted region increased with the implanted ions dose, which can act as high-diffusivity path and oxide core. Comparing to un-implanted IC6 alloy, Y-implantation increased the oxidation rate of IC6 alloy in initial 25 h at 1100°C, but decreased the maximum weight gain and the oxidation rate in final period. Moreover, the oxide scales of Y-implanted IC6 alloy were more continuous and compact due to the benefit effect of yttrium, and had better coherence to substrate through reduction of oxide grain size resulting in oxide scale plasticity improvement. Hence the proper amount of implanted Y could improve the oxidation resistance of IC6 alloy at 1100°C in air slightly.
Authors: Zhi Guang Liu, Chang Jiang Zhang, Li Hua Chai, Yu Yong Chen, Kee Do Woo
Abstract: A near-α high temperature titanium alloy, Ti-6Al-2.5Sn-4Zr-0.7Mo-0.30Si, was produced with various Y contents from 0 to 0.7wt% by arc-melting technique to study the influence of Y on its microstructure and mechanical properties. It was found that small amount of Y obviously refines the grain size of Ti-6Al-2.5Sn-4Zr-0.7Mo-0.30Si alloy. SEM and TEM observations revealed that Y-containing phase precipitated at the β grain boundary in the form of Y2O3 particles. Hardness and compression tests performed at room temperature revealed the strengthening effect of Y.
Authors: Rosli Ahmad, Ashraf M.M. Elaswad, M.B.A. Asmael, N.R. Shahizan
Abstract: The effect of the rare earth (RE) element Y on the microstructure and hardness of (Mg–0.5Zn–0.5Zr–2.8Nd –1.5Gd) wt% Mg alloy investigated. 1 wt. % Y was added and compared with the base alloy. The microstructure results show the refinement of the grain by the addition of Y and the grains became smaller about 31.8 % and the volume fraction was increases 11.1% %, which led to the increment of hardness from 48.33 HV (as-cast EV31A) to 53.71 HV (as-cast EV31A +1 Y). Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) results showed that the base alloy mainly contained α-Mg matrix and Mg-(Nd, Gd) as a second phase crystallized along the grain boundaries and addition of (Y) yttrium resulted in the formation of the new phase, Mg-Zn-Y-phase was found as a new ternary phase, where Y combined with the original second phase.
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