Chemical alteration of 238Pu-loaded borosilicate glass under saturated leaching conditions

2019 ◽  
Vol 108 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Bella Yu. Zubekhina ◽  
Andrei A. Shiryaev ◽  
Boris E. Burakov ◽  
Irina E. Vlasova ◽  
Alexey A. Averin ◽  
...  
Keyword(s):  
Borosilicate Glass ◽  
Laser Power ◽  
Local Environment ◽  
Chemical Compositions ◽  
Bulk Glass ◽  
Photoluminescence Spectra ◽  
Aluminum Hydroxides ◽  
Model Glass ◽  
Optical Bleaching ◽  
Peculiar Behavior

Abstract Highly radioactive 238Pu-doped and non-radioactive samples of borosilicate glass with chemical compositions and synthesis routine similar to SON68 glass were studied under static saturated leaching conditions in distilled water at 90 °C. Dramatic differences in behavior of the radioactive and model glasses were observed. On time scale of 4 months the radioactive glass is fully covered by mechanically unstable alteration layer, possibly consisting of aluminum hydroxides with small fraction of a separate secondary Pu bearing phase. The model glass remains virtually pristine. Addition of Eu3+ into the glass allowed examination of the glass radio- and photoluminescence and to assess changes or REE3+ impurity local environment during self-irradiation and leaching. Photoluminescence spectra suggest more ordered local environment of europium ions in the alteration “gel” than in the bulk glass. Peculiar behavior of the photoluminescence spectra excited at different laser power is observed for the alteration layer and is ascribed to optical bleaching of color centers.

Optical Absorption and Photoluminescence Properties of Dy3+ Ions in Bi2O3-SiO2-B2O3 Glass System

2014 ◽  
Vol 979 ◽  
pp. 280-284
Author(s):  
Narong Sangwaranatee ◽  
Yaowaluk Tariwong ◽  
Sunisa Sarachai ◽  
Jakrapong Kaewkhao ◽  
Natthakridta Chanthima
Keyword(s):  
Optical Absorption ◽  
Emission Spectrum ◽  
Molar Volume ◽  
Borosilicate Glass ◽  
Excitation Wavelength ◽  
Optical Absorption Spectra ◽  
Photoluminescence Spectra ◽  
Photoluminescence Properties ◽  
Melt Quenching ◽  
Absorption Bands

This research studied the effect of dysprosium on the physical, optical and luminescence properties of the bismuth borosilicate glass in compositions 40Bi2O3 : 20SiO2 : (40-x)B2O3 : xDy2O3 (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%). The glass systems have been prepared at 1100 °C by melt quenching technique. The results showed that the density and molar volume of glass samples are between 4.6477 ± 0.0020 to 5.0047 ± 0.0041 g/cm3 and 45.6608 to 48.6797 cm3/mol, respectively. The values of density and molar volume of these glasses were not depend on the Dy2O3 concentration. The optical absorption spectra of glass samples in the UV-Vis-NIR region shows absorption bands at 794, 906, 1094, 1276 and 1690 nm, respectively. The photoluminescence spectra show emission bands at 482 (blue), 576 (green), 663 (yellow) and 756 (red) nm under 453 nm excitation wavelength. The emission spectrum at 576 nm has shown a strongest intensity.

Laser-Induced Dry Etching of GaAs with High Aspect Ratio

1991 ◽  
Vol 236 ◽  
Author(s):  
Cheon Lee ◽  
Hirokazu Sayama ◽  
Susumu Namba ◽  
Mikio Takai
Keyword(s):  
Aspect Ratio ◽  
Electron Spectroscopy ◽  
Laser Power ◽  
Chemical Compositions ◽  
Reaction Products ◽  
Scan Speed ◽  
Ion Laser ◽  
Etched Surface ◽  
Argon Ion ◽  
Scattering Measurement

AbstractLaser-induced thermochemical reactions have been investigated for GaAs in a CCl2F2 gas ambient using an argon-ion laser. The chemical compositions of the reaction products deposited on the etched groove were measured by Auger electron spectroscopy (AES). The conditions of laser power, scan speed, and CC12F2 gas pressure under which the etching reaction occurs without deposition of the residue were clarified. High etching rates up to 267 μm/s and an aspect ratio of 4.5 have been achieved by a single scan of a laser beam. Microprobe photoluminescence and Raman scattering measurement were carried out on the etched surface to characterize damage induced by this processing.

scholarly journals Optimization of Process Parameters, Microstructure, and Properties of Laser Cladding Fe-Based Alloy on 42CrMo Steel Roller

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2061 ◽  
Author(s):  
Jiang Ju ◽  
Yang Zhou ◽  
Maodong Kang ◽  
Jun Wang
Keyword(s):  
Laser Cladding ◽  
Process Parameters ◽  
Laser Power ◽  
Salt Spray ◽  
Continuous Casting Machine ◽  
Scanning Speed ◽  
Optimum Process ◽  
Chemical Compositions ◽  
Cladding Layer ◽  
42Crmo Steel

The mould foot roller is a key component of a continuous casting machine. In order to investigate the possibility of using laser cladding to repair mould foot roller, Fe-based powders and 42CrMo steel are used in this work. The laser cladding process parameters were optimized by orthogonal experiments. The chemical compositions, microstructure, properties of the cladding layer under the optimum process parameters, and substrate were systematically investigated by using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness test, wear test, and salt spray corrosion test. The results indicate that the primary factor affecting the width and depth of the cladding layer is laser power. The scanning speed also has a significant effect on the height of the cladding layer. The optimum process parameters for repairing the mould foot roller are 2 kW laser power, 4 mm/s scanning speed, and 15 g/min feeding rate of powder. Along the depth direction of the cladding layer, the microstructure of the coating gradually transforms from plane crystal, cell grains, or dendrites to equiaxed grains. The matrix is mainly martensite with retained austenite; the eutectic phase is composed of netlike M2B, particulate M23(C,B)6, and M7(C,B)3 phase. The hardness of the cladding layer is significantly improved, about three times that of the substrate. The weight loss of the cladding layer is just half that of the substrate. Its wear resistance and corrosion resistance have been significantly improved. The work period of the laser cladding-repaired foot roller is much longer than for the surfacing welding-repaired one. In summary, laser cladding technology can increase the life of mould foot rollers.

Copper Laser Induced Chemical Vapor Deposition of al Films

1990 ◽  
Vol 201 ◽  
Author(s):  
M. I. Yankova ◽  
W. Shanov ◽  
B. Ivanov
Keyword(s):  
Laser Power ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Single Step ◽  
Laser Power Density ◽  
Chemical Compositions ◽  
Silicon Substrates ◽  
Direct Writing ◽  
Scanning Velocity

AbstractThe focused output from a copper laser (λ = 510nm) has been used for direct writing of Al on silicon substrates by pyrolitical decomposition of trimethilaluminum (TMA). These results demonstrate that direct writing can be accomplished at room temperature by a single-step deposition process induced by a single light source. For a laser power density between 5 and 50 kW cm−2, the widths of the stripes varied between 60 and 200 μm with corresponding thickness between 0.5 and 0.8 μm. The width of the stripes proved to be independent of the scanning velocity, Vs, within the range 50 μm s−1 < Vs < 300 μm s−1. The analysis included scanning electron microscopy (SEM) to study the film morphology, a step profiler to evaluate the thicknesses and the profiles of the stripes, and energy dispersive spectroscopy (EDS) to provide their chemical compositions.

Investigation of local environment around rare earths (La and Eu) by fluorescence line narrowing during borosilicate glass alteration

2014 ◽  
Vol 145 ◽  
pp. 213-218 ◽  
Author(s):  
Estelle Molières ◽  
Gérard Panczer ◽  
Yannick Guyot ◽  
Patrick Jollivet ◽  
Odile Majérus ◽  
...  
Keyword(s):  
Rare Earths ◽  
Borosilicate Glass ◽  
Local Environment ◽  
Line Narrowing ◽  
Fluorescence Line ◽  
Fluorescence Line Narrowing

Triboluminescence of Rare-Earth-Doped Aluminosilicates and Its Application to Sensing of Structural Damage

1999 ◽  
Vol 604 ◽  
Author(s):  
Katsuhisa Tanaka ◽  
Tsuguo Ishihara ◽  
Koji Fujita ◽  
Kazuyuki Hirao
Keyword(s):  
Rare Earth ◽  
Structural Damage ◽  
Local Environment ◽  
Rare Earth Ions ◽  
Emission Lines ◽  
Photoluminescence Spectra ◽  
The Difference ◽  
Ligand Fields ◽  
Rare Earth Doped ◽  
The Eu

AbstractIntense triboluminescence has been observed in rare-earth-doped aluminosilicates such as BaAl2Si2O8and SrAl2Si2O8doped with Eu2+, Tb3+, or Dy3+. The triboluminescence is caused by the excitation of and emission from rare-earth ions doped in the crystals. A discrepancy in the wavelength of maximum emission intensity between triboluminescence and photoluminescence spectra is observed for the 4f65d-4f7 transition of Eu2+, whereas the peak positions and the relative intensities of emission lines in triboluminescence and photoluminescence spectra are almost the same as each other for the 4f-4f transitions of Th3+ and Dy3+. This is because the 5d levels, which are more significantly affected by ligand fields than the 4f levels, contribute to the transition of Eu2+. It is thought that the difference in local environment around the Eu2+ between on the fractured surface and within the bulk brings about the discrepancy between triboluminescence and photoluminescence spectra

Hydrothermal Leaching of R7-T7 Borosilicate Glass

1989 ◽  
Vol 176 ◽  
Author(s):  
J. Caurel ◽  
E. Vemaz ◽  
D. Beaufort
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Borosilicate Glass ◽  
Type Equation ◽  
Amorphous Layer ◽  
Bulk Glass ◽  
Surface Layers ◽  
Glass Dissolution ◽  
One Year

ABSTRACTThe results of hydrothermal leach tests are intended to be used to predict long-term low-temperature glass dissolution. It is often assumed that data can be extrapolated to other conditions using an Arrhenius-type equation. Hydrothermal leaching mechanisms and their temperature dependence in R7T7 glass were investigated in static experiments lasting from 7 days to 1 year at 150°C and 250°C. Leachates, surface layers and crystalline products were analyzed by ICP, TEM, SEM, EMP, XRD and cathodoluminescence. Unexpectedly, no actual saturation conditions in solutions were reached after one year leaching at 150°C nor at 250°C. The effect of precipitation of alteration products (a silica-enriched amorphous layer and aluminosilicates [smectite at 150°C, smectite and zeolites at 250°C]) is discussed. However, the formation of large cracks in the bulk glass results in a higher glass reacting surface and a higher dissolution rate at 250°C. Arrhenius calculations cannot be used to extrapolate our hydrothermal data to lower-temperatures.

scholarly journals A PRIORI ASSESSMENT OF THE EFFECTIVENESS AND LIMITS OF APPLICABILITY OF COLEMANITE AS GLASS RAW MATERIALS

2017 ◽  
Vol 2 (3) ◽  
pp. 70-75 ◽  
Author(s):  
Скурятина ◽  
Elena Skuryatina ◽  
Жерновая ◽  
Natalya Zhernovaya ◽  
Онищук ◽  
...  
Keyword(s):  
Phase Separation ◽  
Boric Acid ◽  
Calcium Oxide ◽  
Borosilicate Glass ◽  
Boron Oxide ◽  
Raw Materials ◽  
A Priori ◽  
Chemical Compositions ◽  
Calcium Borate ◽  
Wide Range

Borosilicate glass has a wide range of chemical compositions. Relevant is the question of finding quality and affordable boron-containing raw materials. OOO &#34;Ecoprodukt» offers replacement of boric acid on the calcium borate colemanite, which leads to the obligatory presence in the glass of boron oxide and calcium oxide, and contributes to certain technical difficulties. Thus it makes sense to execute research of stekloobrazovaniya, phase separation and properties of glasses in the system of records &#34;colemanite-soda-sand&#34; with wide limits of variation of oxides in experimental glasses.

Laser Modification of Silicon and Borosilicate Glass Wettability for Micro-Fluidic Systems

2015 ◽  
Vol 9 (6) ◽  
pp. 668-673 ◽  
Author(s):  
Yuko Aono ◽  
◽  
Wataru Shinohara ◽  
Hitoshi Tokura
Keyword(s):  
Laser Irradiation ◽  
Borosilicate Glass ◽  
Laser Power ◽  
Micro Channel ◽  
Laser Modification ◽  
Deep Groove ◽  
Infrared Laser Irradiation ◽  
Modification Method ◽  
Ft Ir ◽  
Proposed Modification

A laser modification method to control the surface wettability of a silicon and borosilicate glass substrate is proposed and demonstrated. The wettability of the silicon surface decreases after 2.5 W laser irradiation without a change in surface morphology. When the laser power is greater than 4 W, it results in the formation of a 10-nm-deep groove and the wettability increases. These phenomena are caused by changes in the number of surface groups and morphology, respectively. On the other hand, the glass surface is modified by infrared laser irradiation and the treated surface is highly hydrophilic. Surface analysis by FT-IR indicates that the modification is the result of an increase in the number of silanol groups. The proposed modification method is applied to micro-fluidic systems. A modified line can function as a surface micro-channel. Furthermore, with a gradient in wettability, the micro-channel has the ability to self-transport water droplets.

Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations

1969 ◽  
Vol 27 ◽  
pp. 82-83
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Local Environment ◽  
Chamber Pressure ◽  
Objective Lens ◽  
Ion Pump ◽  
Quantitative Studies ◽  
Precise Knowledge ◽  
Differential Pumping ◽  
And Control

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.

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