ChemInform Abstract: SYNTHESIS AND X-RAY DIFFRACTION STUDY OF SOME NEW RARE EARTH ELEMENT SELENIDE IODIDES

1984 ◽  
Vol 15 (35) ◽  
Author(s):  
I. V. PROTSKAYA ◽  
V. A. TRIFONOV ◽  
B. A. POPOVKIN ◽  
A. V. NOVOSELOVA ◽  
S. I. TROYANOV ◽  
...  
Keyword(s):  
Rare Earth ◽  
Diffraction Study ◽  
Rare Earth Element ◽  
Earth Element ◽  
X Ray Diffraction ◽  
X Ray

Rare-earth crystal chemistry of thalénite-(Y) from different environments

2018 ◽  
Vol 82 (2) ◽  
pp. 313-327
Author(s):  
Markus B. Raschke ◽  
Evan J. D. Anderson ◽  
Jason Van Fosson ◽  
Julien M. Allaz ◽  
Joseph R. Smyth ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Spatial Scales ◽  
Structure Refinement ◽  
X Ray Diffraction ◽  
Heavy Rare Earth ◽  
Heavy Rare Earth Element ◽  
X Ray ◽  
Golden Horn

ABSTRACTThalénite-(Y), ideally Y3Si3O10F, is a heavy-rare-earth-rich silicate phase occurring in granite pegmatites that may help to illustrate rare-earth element (REE) chemistry and behaviour in natural systems. The crystal structure and mineral chemistry of thalénite-(Y) were analysed by electron microprobe analysis, X-ray diffraction and micro-Raman spectroscopy from a new locality in the peralkaline granite of the Golden Horn batholith, Okanogan County, Washington State, USA, in comparison with new analyses from the White Cloud pegmatite in the Pikes Peak batholith, Colorado, USA. The Golden Horn thalénite-(Y) occurs as late-stage sub-millimetre euhedral bladed transparent crystals in small miarolitic cavities in an arfvedsonite-bearing biotite granite. It exhibits growth zoning with distinct heavy-rare-earth element (HREE) vs. light-rare-earth element (LREE) enriched zones. The White Cloud thalénite-(Y) occurs in two distinct anhedral and botryoidal crystal habits of mostly homogenous composition. In addition, minor secondary thalénite-(Y) is recognized by its distinct Yb-rich composition (up to 0.8 atoms per formula unit (apfu) Yb). Single-crystal X-ray diffraction analysis and structure refinement reveals Y-site ordering with preferential HREE occupation of Y2 vs. Y1 and Y3 REE sites. Chondrite normalization shows continuous enrichment of HREE in White Cloud thalénite-(Y), in contrast to Golden Horn thalénite-(Y) with a slight depletion of the heaviest REE (Tm, Yb and Lu). The results suggest a hydrothermal origin of the Golden Horn miarolitic thalénite-(Y), compared to a combination of both primary magmatic followed by hydrothermal processes responsible for the multiple generations over a range of spatial scales in White Cloud thalénite-(Y).

Effect of Conjoint Additions of Rare Earth Element Oxides on the Phase Stability of Zirconia

1995 ◽  
Vol 412 ◽  
Author(s):  
Ewan R. Maddrell
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Oxide Phase ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconium Butoxide ◽  
Pyrochlore Type

AbstractThe ability of the cubic phase of zirconia to accommodate in solid solution the oxides of rare earth elements with differing cationic radii has been investigated. Mixed oxide phase assemblages were prepared by hydrolysing zirconium butoxide with solutions of rare earth element nitrates followed by drying, calcining and sintering. The resulting products were characterised by X-ray diffraction and energy dispersive spectroscopy. The cubic zirconia phase can accept into solid solution the larger, non-cubic stabilising, rare earth element ions such as lanthanum in the presence of the cubic stabilising oxides of yttrium and samarium. As the proportion of the larger rare earth element ions is increased the formation of pyrochlore type compounds is favoured.

Preparation of Ceria from Bastnaesite with NaHCO3 as Fluoride Retention Additive

2013 ◽  
Vol 477-478 ◽  
pp. 1423-1427
Author(s):  
Hui Zhong ◽  
Ke Hui Qiu ◽  
Yu Chong Qiu ◽  
Yu Tao Li ◽  
Ning Jia Fu
Keyword(s):  
Rare Earth ◽  
Hydrochloric Acid ◽  
Sodium Bicarbonate ◽  
Rare Earth Element ◽  
Earth Element ◽  
Rare Earth Oxide ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Elements

The CeO2 is prepared directly from bastnaesite as raw material that originated in Dechang, Sichuan province, China. Fully mixed with sodium bicarbonate (NaHCO3) and roasted at 550 °C, the rare earth element (REE) in bastnaesite transformed into rare earth oxide. And the CeO2 will be obtained by removing NaF through water washing and leaching the impurity elements including La, Fe, Al, Ca, etc. via hydrochloric acid (HCl). The CeO2 was characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The XRF results demonstrated that the content of CeO2 could reach more than 70% in products which can be used as polishing material.

Rare earth disilicates R2Si2O7 (R = Gd, Tb, Dy, Ho): type B

2003 ◽  
Vol 218 (12) ◽  
Author(s):  
Michael E. Fleet ◽  
Xiaoyang Liu
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Element ◽  
Room Temperature ◽  
Earth Element ◽  
Type B ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature And Pressure

AbstractThe type B structure of the single rare earth element disilicates has been revised using room temperature and pressure single-crystal X-ray diffraction measurements on Gd

scholarly journals Corrosion and mechanical properties of AM50 magnesium alloy after modified by different amounts of rare earth element Gadolinium

Open Physics ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 444-451 ◽  
Author(s):  
Miao Yang ◽  
Zhiyi Zhang ◽  
Yaohui Liu ◽  
Xianlong Han
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Rare Earth Element ◽  
Earth Element ◽  
Mechanical Stretch ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

AbstractTo improve the corrosion and mechanical properties of the AM50 magnesium alloy, different amounts of the rare earth element gadolinium were used. The microstructure, corrosion and mechanical properties were evaluated by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and electrochemical and mechanical stretch methods. The results indicate that, with Gd addition, the amount of the Al2Gd3 phase increased while the β-Mg17Al12 phase amount decreased. Due to the Gd addition, the grain of the AM50 magnesium alloy was significantly refined, which improved its tensile strength. Further, the decrease in the amount of the β phase improved the corrosion resistance of the alloy. The fracture mechanism of the Gd-modified AM50 magnesium alloy was a quasi-cleavage fracture. Finally, the optimum corrosion residual strength of the AM50 magnesium alloy occurred with 1 wt.%of added Gd.

Suppression of BaF2 Slow Component of X-RAY Luminescence in Non-Stoichiometric Bao.9R0.1F2.1 Crystals (R=Rare Earth Element)

1994 ◽  
Vol 348 ◽  
Author(s):  
B.P. Sobolev ◽  
E.A. Krivandina ◽  
S.E. Derenzo ◽  
W.W. Moses ◽  
A.C. West
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Dopant Concentration ◽  
Slow Component ◽  
Light Output ◽  
Fast Component ◽  
Significant Suppression ◽  
Low Light ◽  
X Ray

ABSTRACTA series of BaF2 crystals doped with 10% mole fraction of each rare earth element has been grown, and the effect of these dopants on the slow luminescence (due to anionic self trapped excitons) and fast luminescence (due to core-valence transitions) has been studied. While significant suppression was observed for both components, the best dopants for suppressing the slow component of barium fluoride (up to 25-50%) while maintaining the luminosity of the fast component are La, Y, and Lu. The luminescence of Ba0.9Eu0.1F2.1 is almost entirely fast (>90%), but with low light output. For two rare earth dopants (La and Gd), the effect of slow and fast component suppression was studied as a function of concentration (Ba1-xRxF2+x with x≦0.5 for R=La and x≦0.3 for R=Gd). The suppression is non-linear with dopant concentration, with the relative degree of slow component suppression correlated with the melting point of these samples.

Influence of Casting Conditions and Alloy Additions on the Zn22Al2Cu Structure

2012 ◽  
Vol 326-328 ◽  
pp. 547-554 ◽  
Author(s):  
Rafał Michalik ◽  
A. Tomaszewska ◽  
H. Woźnica
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Optical Microscope ◽  
Alloy Structure ◽  
Unmodified Alloy ◽  
X Ray ◽  
Total Replacement ◽  
Cu Alloy ◽  
Cu Alloys

Zn-Al-Cu alloys are characterized by a number of beneficial properties that include good castability, good tribological properties and low energy input for forming the product. When compared to bronze, Zn-Al-Cu alloys have a lower density. Properties of Zn-Al-Cu can be improved by the partial or total replacement of copper with silicon and rare earth element additions. In the literature there are few studies on the effect of casting conditions and modifying the chemical composition through the introduction of alloy micro-additives on the alloy structure. The aim of this study was to determine the effect of casting conditions and silicon and rare earth element additions on the structure of Zn-22% Al-2%Cu alloy. The subjects examined were the unmodified alloy, the alloy with 1.5% Si and the alloy with 1.5% Si and rare earth elements (mich metal). Samples were cast in sand and graphite molds. The liquidus temperature for each of these examined samples was determined. Structure examinations were carried out in samples taken from the top, center and bottom of the ingot. In order to determine the microstructure of the examined structures metallographic examinations using an optical microscope and a scanning electron microscope with energy dispersive spectroscopy (EDS) capabilities, an X-ray microscope, was performed. Quantitive analysis on specific, characteristic microzones was performed based on the EDS X-ray spectroanalysis results.

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