M�ssbauer and X-ray photoelectron spectroscopic studies of heat-treated calcium borate glasses containing iron

Phosphate glasses in the system (50-x)A2O-xMoO3-10Nb2O5-40P2O5 (AMo-40), with x=0; 30 and A=Li or Na were prepared by the melt quenching method. The effect in the crystallization behaviour of the glass due to the introduction of MoO3 in the glass composition and varying the molar ratio between network modifiers and network formers (M/F) was studied. The prepared glasses were heat-treated in air, at 550, 600 and 650 ºC for 4 hours. The structure, of the obtained samples, was studied by differential thermal analysis (DTA), X-ray powder diffraction (XRD), Raman spectroscopy and the morphology by scanning electron microscopy (SEM). It was found that the replacement of Li2O or Na2O by MoO3 reduces the number of the crystallised phases. In the lithium-niobiophosphate glasses the presence of MoO3 promotes the formation of NbOPO4 and reduces the formation of ortho- and pyro-phosphate phases. The thermal treatments affect the arrangements of the network structure of the AMo-40-glasses.

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Temperature-Controlled Devitrification of Oxyfluoride Borate Glasses

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.130.263 ◽

2007 ◽

Vol 130 ◽

pp. 263-266 ◽

Cited By ~ 3

Author(s):

Joanna Pisarska ◽

Tomasz Goryczka ◽

Wojciech A. Pisarski

Keyword(s):

Heat Treatment ◽

Glass Ceramics ◽

Borate Glasses ◽

X Ray Diffraction ◽

Transparent Glass ◽

X Ray ◽

Heat Treated ◽

Before And After ◽

Controlled Crystallization ◽

Temperature Controlled

Selected oxyfluoroborate glasses have been investigated before and after heat treatment. Transparent glass-ceramics (TGC) were obtained during controlled crystallization (devitrification). X-ray diffraction studies confirmed that material was partially crystallized. Diffraction lines due to orthorhombic PbF2 phase were identified for heat-treated samples at various temperatures and times. Results were compared to that ones obtained for as-melted glass.

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Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078377 ◽

1977 ◽

Vol 35 ◽

pp. 162-163

Author(s):

Thomas R. McKee ◽

Peter R. Buseck

Keyword(s):

Crystallite Size ◽

Sedimentary Rocks ◽

Carbonaceous Material ◽

Low Grade ◽

X Ray ◽

Graphitized Carbon ◽

Transmission Electron ◽

Heat Treated ◽

Commercial Carbon ◽

Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

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The effect of small additions of Cu on precipitation in Al-Mg-Si alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135812 ◽

1990 ◽

Vol 48 (2) ◽

pp. 442-443

Author(s):

M. Tamizifar ◽

G. Cliff ◽

R.W. Devenish ◽

G.W. Lorimer

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Scanning Transmission Electron Microscope ◽

Argon Atmosphere ◽

Age Hardening ◽

X Ray ◽

Transmission Electron ◽

Heat Treated ◽

Analytical Electron ◽

Scanning Transmission

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.

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Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173959 ◽

1990 ◽

Vol 48 (4) ◽

pp. 164-165

Author(s):

Noriyuki Kuwano ◽

Masaru Itakura ◽

Kensuke Oki

Keyword(s):

Electron Microscopy ◽

Mean Value ◽

Heavy Elements ◽

Arc Furnace ◽

X Ray ◽

Long Period ◽

Ultra High Purity ◽

Heat Treated ◽

Atomic Scattering ◽

The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

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Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

Journal of Electronic Materials ◽

10.1007/s11664-021-09067-4 ◽

2021 ◽

Author(s):

A. Leineweber ◽

M. Löffler ◽

S. Martin

Keyword(s):

Phase Equilibria ◽

Electron Backscatter Diffraction ◽

Metastable Phase ◽

Stable Phase ◽

X Ray Diffraction ◽

X Ray ◽

Heat Treated ◽

Ordered Phases ◽

Backscatter Diffraction ◽

Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

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Phase Relations in the ZrO2-MgO-FeOx System: Experimental Data and Assessment of Thermodynamic Parameters

Journal of Phase Equilibria and Diffusion ◽

10.1007/s11669-021-00876-y ◽

2021 ◽

Author(s):

Ivan Saenko ◽

O. Fabrichnaya

Keyword(s):

Electron Microscopy ◽

Experimental Data ◽

Solid Solution ◽

Thermodynamic Parameters ◽

Spinel Phase ◽

Experimental Investigations ◽

X Ray ◽

Heat Treated ◽

Preliminary Phase ◽

Scanning Electron

AbstractThermodynamic parameters were assessed for the MgO–FeOx system and combined with already available descriptions of ZrO2-FeOx and ZrO2-MgO systems to calculate preliminary phase diagrams for planning experimental investigations. Samples of selected compositions were heat treated at 1523, 1673 and 1873 K and characterized using x-ray and scanning electron microscopy combined with energy dispersive x-ray spectroscopy (SEM/EDX). Experiments indicated extension of cubic ZrO2 solid solution into the ternary system at 1873 K (75 mol.% ZrO2, 10 mol.% FeOx and 15 mol.% MgO) and limited solubility of 4 mol.% ZrO2 in spinel phase. Based on the obtained results thermodynamic parameters of C-ZrO2 and spinel phase were optimized.

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