A mass spectrometric study of Al2O3‐SiO2 melts using a Knudsen cell

Björkvall, Johan; Stolyarova, V. L.

doi:10.1002/rcm.251

Cited by 26 publications

(26 citation statements)

References 13 publications

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“…As reported by Toropov and Galakhov [8], heating of aluminosilicate materials in vacuum gives rise to selective SiO 2 vaporization, which changes the phase composition of the condensed phase. Most of the studies in question used high-temperature mass spectrometry [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. The thermodynamic properties of the Al 2 O 3 -SiO 2 system were assessed by examining vaporization processes and evaluating the partial pressures of vapor species over Al 2 O 3 -SiO 2 in a broad temperature range.…”

Section: Introductionmentioning

confidence: 99%

High-temperature thermodynamic properties of the Al2O3-SiO2 system

2005

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Section: Introductionmentioning

confidence: 99%

High-temperature thermodynamic properties of the Al2O3-SiO2 system

2005

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“…Experiments have been conducted to determine the speciation and concentration of vapor-phase constituents from multicomponent systems, including silicates [111,112], though these compositions diverge substantially, and are thus not relevant, to fallout glasses from this study. However, a similar technique (i.e., Knudsen effusion mass spectrometry) could be applied, along with high-temperature vaporization experiments, to a multicomponent system reflecting fallout glass composition.…”

Section: Determining the Relative Volatilities Of Species In A Multicmentioning

confidence: 99%

Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

Weisz¹

2016

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In a near-surface nuclear explosion, vaporized device materials are incorporated into molten soil and other carrier materials, forming glassy fallout upon quenching. Mechanisms by which device materials mix with carrier materials have been proposed, however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. A surface deposition layer was observed preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused. Eleven such boundaries were studied using spatially resolved analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nano-scale secondary ion mass spectrometry (NanoSIMS), we identified higher concentrations of uranium from the device in 7 of the interface layers, as well as isotopic enrichment (>75% 235 U) in 9 of the interface layers. Major element analysis of the interfaces revealed the deposition layer to be chemically enriched in Fe-, Ca-and Na-bearing species and depleted in Ti-and Al-bearing species. The concentration profiles of the enriched species at the interface are characteristic of diffusion. Three of the uranium concentration profiles were fit with a modified Gaussian function, representative of 1-D diffusion from a planar source, to determine time and temperature parameters of mass transport. By using a historical model of fireball temperature to simulate the cooling rate at the interface, the temperature of deposition was estimated to be ∼2200 K, with 1σ uncertainties in excess of 140 K. The presence of Na-species in the layers at this estimated temperature of deposition is indicative of an oxygen rich fireball. The notable depletion of Al-species, a refractory oxide that is highly abundant in the soil, together with the enrichment of Ca-, Fe-, and 235 U-species, suggests an anthropogenic source of the enriched species, together with a continuous chemical fractionation process as these species condensed.

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“…The same method was used in [20] Modelling a Al 2 O 3 of the system mixtures in the entire compositional range was performed in works [22,23] using a package of applied software Thermocalc and Factsage, respectively. SiO 2 activities determined in these works, are given in Figure 2.…”

Section: Abstract : Aluminium and Silicon Oxides Constitutionmentioning

confidence: 99%

Prediction of thermodynamic properties of Al2O3-SiO2 system melts

Goncharov¹,

Galinich²,

Mishchenko³

et al. 2015

The Paton Welding J.

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Aluminium and silicon oxides are included into the composition of fluxes for welding, electroslag remelting and metallurgical slags. Knowledge of thermodynamic properties of aluminium oxide-silicon oxide system mixtures will allow evaluation of the nature of their interaction in the melt that will provide an insight into the metallurgical properties of the respective materials for welding and related technologies developed on their base. Analysis of published data on phase equilibria of constitutional diagrams of aluminium oxide-silicon oxide system and thermodynamic properties of this system was performed. It is established that the constitutional diagram data are correct, and experimental values of activities of these melt components are characterized by large scatter. The coordinates of liquidus line of the constitutional diagram of aluminium oxide-silicon oxide system were used to calculate the thermodynamic activities of aluminium oxide at its concentration in the range of 0.7-1.0. It is established that they start manifesting small negative deviations from ideal solutions in the eutectic melt (0.74). Integration of Gibbs-Dugem equation was performed to assess the activities of silicon oxide. It was determined that they demonstrate slight negative deviations from ideal solutions. It is shown that the influence of aluminium oxide-silicon oxide system melts on the nature of interaction in complex multicomponent solutions can be significant. It is found that addition of thermodynamically stable chemical compounds (for instance, sillimanite) to multicomponent slag melts leads to lowering of their oxidizing ability. Replacement of quartz sand and alumina by disthensillimanite concentrate in agglomerated flux charge leads to lowering of thermodynamic activity of oxygen in the slag melt, slows down running of silicon-reduction process and reduces manganese losses in welding. 25 Ref.,6 Figures. K e y w o r d s : aluminium and silicon oxides, constitutional diagrams, thermodynamic activity of components, slag melts, fluxes for welding and electroslag remeltingAluminium and silicon oxides are included into the fluxes for welding, electroslag remelting and metallurgical slags [1]. In multicomponent slag melts on their base, complex alumosiliconoxygen anions of different degrees of polymerization form, which determine the melt physico-chemical properties, and technological and metallurgical properties of the respective materials, accordingly. Knowledge of thermodynamic properties of Al 2 O 3 -SiO 2 system melts is required to predict the thermodynamic properties of the respective ternary and quaternary slag systems, which include binary Al 2 O 3 -SiO 2 system, and improvement of currently available welding fluxes and metallurgical slags.In this connection, the objective of this work was analysis of the available published data on phase equilibria and thermodynamic properties of Al 2 O 3 -SiO 2 system mixtures, as well as calculation of activity of components of liquid solutions, proceeding from the coordinates of liqui...

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A mass spectrometric study of Al₂O₃‐SiO₂ melts using a Knudsen cell

Cited by 26 publications

References 13 publications

High-temperature thermodynamic properties of the Al2O3-SiO2 system

High-temperature thermodynamic properties of the Al2O3-SiO2 system

Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

Prediction of thermodynamic properties of Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> system melts

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