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N I Matskevich - One of the best experts on this subject based on the ideXlab platform.

  • thermochemical characteristics of strontium Cerate doped by neodymium and indium oxides
    Mendeleev Communications, 2020
    Co-Authors: N I Matskevich, A N Semerikova, O I Anyfrieva, Mariya Yu Matskevich, Evgeniy N Tkachev
    Abstract:

    The thermodynamic functions (formation enthalpy and stabilization energy) of SrCe0.7Nd0.2In0.1O2.85 were measured to demonstrate that strontium Cerate doped by neodymium and indium oxides has higher stabilization energy than that of undoped strontium Cerate. The result obtained can give advantage to apply this compound in comparison with SrCeO3.

  • enthalpy of formation of in gd doped barium Cerate
    Thermochimica Acta, 2015
    Co-Authors: N I Matskevich, Th. Wolf, A N Semerikova, P Adelmann, O I Anyfrieva
    Abstract:

    Abstract Solution enthalpies of barium Cerate doped by gadolinium and indium and a mixture of BaCl2 + 0.7CeCl3 + 2GdCl3 + 0.1InCl3 have been measured in 1 mol dm−3 HCl with 0.1 mol dm−3 KI. For the first time the standard molar formation enthalpy of BaCe0.7Gd0.2In0.1O2.85 has been determined by solution calorimetry as follows: ΔfH° (298.15 K) = −1615.84 ± 9.01 kJ mol−1. The stabilization energy for above-mentioned compound has been calculated as well. It has been shown that barium Cerate doped gadolinium and indium has higher stabilization energy than BaCe0.7Nd0.2In0.1O2.85 and BaCeO3. The reaction enthalpy with CO2 interaction has been calculated for BaCe0.7Gd0.2In0.1O2.85.

  • thermodynamic stability and hydration enthalpy of strontium Cerate doped with yttrium
    Thermochimica Acta, 2006
    Co-Authors: N I Matskevich, Yu G Stenin, Th. Wolf, Yu M Matskevich
    Abstract:

    Abstract The standard molar enthalpy of formation of SrY 0.05 Ce 0.95 O 2.975 has been derived by combining the enthalpy of solution in 1 M HCl + 0.1 KI with auxiliary literature data, Δ f H ° (SrY 0.05 Ce 0.95 O 2.975 , s, 298.15 K) = −1720.4 ± 3.4 kJ/mol. The formation enthalpy of SrY 0.05 Ce 0.95 O 2.975 from the mixture of binary oxides is Δ ox H ° (298.15 K) = −45.9 ± 3.4 kJ/mol and the enthalpy of reaction of SrY 0.05 Ce 0.95 O 2.975 with water forming Sr(OH) 2 , CeO 2 , and Y 2 O 3 is Δ r H ° (298.15 K) = −85.5 ± 3.4 kJ/mol. Our data and the entropies of different substances show that SrY 0.05 Ce 0.95 O 2.975 is thermodynamically stable with respect to a mixture of SrO, Y 2 O 3 , CeO 2 and that the reaction of SrY 0.05 Ce 0.95 O 2.975 with water is thermodynamically favourable.

  • short communication thermodynamic stability and hydration enthalpy of strontium Cerate doped with yttrium
    2006
    Co-Authors: N I Matskevich, G Stenin
    Abstract:

    The standard molar enthalpy of formation of SrY0.05Ce0.95O2.975 has been derived by combining the enthalpy of solution in 1 M HCl + 0.1 KI with auxiliary literature data, � fH ◦ (SrY0.05Ce0.95O2.975, s, 298.15 K) = −1720.4 ± 3.4 kJ/mol. The formation enthalpy of SrY0.05Ce0.95O2.975 from the

  • the thermodynamic stability and hydration enthalpy of strontium Cerate doped by yttrium
    arXiv: Materials Science, 2005
    Co-Authors: N I Matskevich, Th. Wolf, Yu M Matskevich
    Abstract:

    The standard molar enthalpy of formation of SrY0.05Ce0.95O2.975 has been derived by combining the enthalpy of solution of this compound in 1 M HCl + 0.1 KI obtained by us and auxiliary literature data. The following value has been derived: DfH (SrY0.05Ce0.95O2.975, s, 298.15 K) = -1720.4 (3.4) kJ/mol. The obtained value has been used to obtain the formation enthalpy of SrY0.05Ce0.95O2.975 from the mixture of binary oxides (DoxH (298.15 K) = -45.9 (3.4) kJ/mol) and formation enthalpy of reaction of SrY0.05Ce0.95O2.975 with water forming Sr(OH)2, CeO2, Y2O3 (DrH (298.15 K) = -85.5 (3.4) kJ/mol). Data obtained by solution calorimetry and additional information on the entropies of different substances have shown that SrY0.05Ce0.95O2.975 is thermodynamically stable with respect to a mixture of SrO, Y2O3, CeO2 and that the reaction of SrY0.05Ce0.95O2.975 with water is thermodynamically favourable.

Abdel Salam Hamdy - One of the best experts on this subject based on the ideXlab platform.

  • corrosion protection of aluminum composites by silicate Cerate conversion coating
    Surface & Coatings Technology, 2006
    Co-Authors: Abdel Salam Hamdy
    Abstract:

    Abstract The effect of silicate surface treatments on the corrosion inhibition characteristics of AA6061 T6-10% Al2O3 composite were studied in 3.5% NaCl. A series of specimens was carried out at different silicate concentrations using different application methods alone or combined with a sealing step in cerium solutions. The effect of surface etching and oxide thickening were also studied. Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion behavior of treated and untreated specimens. The pitting corrosion behavior and the perfect passivity domain were measured using potentiodynamic tests. The occurrence of localized corrosion due to chloride ion attack was examined by optical microscopy and SEM. Generally, silica/ceria treatments improve the corrosion resistance due to the formation of protective oxide films which act as a barrier to oxygen diffusion to the metal surface. Ceria sealing specimens showed a superior corrosion resistance indicating that Cerate and not silicates plays the main part in the passivation mechanism. According to the EIS results, the etching process has a negative effect on the corrosion resistance.

  • corrosion protection of aluminum composites by silicate Cerate conversion coating
    Surface & Coatings Technology, 2006
    Co-Authors: Abdel Salam Hamdy
    Abstract:

    Abstract The effect of silicate surface treatments on the corrosion inhibition characteristics of AA6061 T6-10% Al2O3 composite were studied in 3.5% NaCl. A series of specimens was carried out at different silicate concentrations using different application methods alone or combined with a sealing step in cerium solutions. The effect of surface etching and oxide thickening were also studied. Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion behavior of treated and untreated specimens. The pitting corrosion behavior and the perfect passivity domain were measured using potentiodynamic tests. The occurrence of localized corrosion due to chloride ion attack was examined by optical microscopy and SEM. Generally, silica/ceria treatments improve the corrosion resistance due to the formation of protective oxide films which act as a barrier to oxygen diffusion to the metal surface. Ceria sealing specimens showed a superior corrosion resistance indicating that Cerate and not silicates plays the main part in the passivation mechanism. According to the EIS results, the etching process has a negative effect on the corrosion resistance.

Yu M Matskevich - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic stability and hydration enthalpy of strontium Cerate doped with yttrium
    Thermochimica Acta, 2006
    Co-Authors: N I Matskevich, Yu G Stenin, Th. Wolf, Yu M Matskevich
    Abstract:

    Abstract The standard molar enthalpy of formation of SrY 0.05 Ce 0.95 O 2.975 has been derived by combining the enthalpy of solution in 1 M HCl + 0.1 KI with auxiliary literature data, Δ f H ° (SrY 0.05 Ce 0.95 O 2.975 , s, 298.15 K) = −1720.4 ± 3.4 kJ/mol. The formation enthalpy of SrY 0.05 Ce 0.95 O 2.975 from the mixture of binary oxides is Δ ox H ° (298.15 K) = −45.9 ± 3.4 kJ/mol and the enthalpy of reaction of SrY 0.05 Ce 0.95 O 2.975 with water forming Sr(OH) 2 , CeO 2 , and Y 2 O 3 is Δ r H ° (298.15 K) = −85.5 ± 3.4 kJ/mol. Our data and the entropies of different substances show that SrY 0.05 Ce 0.95 O 2.975 is thermodynamically stable with respect to a mixture of SrO, Y 2 O 3 , CeO 2 and that the reaction of SrY 0.05 Ce 0.95 O 2.975 with water is thermodynamically favourable.

  • the thermodynamic stability and hydration enthalpy of strontium Cerate doped by yttrium
    arXiv: Materials Science, 2005
    Co-Authors: N I Matskevich, Th. Wolf, Yu M Matskevich
    Abstract:

    The standard molar enthalpy of formation of SrY0.05Ce0.95O2.975 has been derived by combining the enthalpy of solution of this compound in 1 M HCl + 0.1 KI obtained by us and auxiliary literature data. The following value has been derived: DfH (SrY0.05Ce0.95O2.975, s, 298.15 K) = -1720.4 (3.4) kJ/mol. The obtained value has been used to obtain the formation enthalpy of SrY0.05Ce0.95O2.975 from the mixture of binary oxides (DoxH (298.15 K) = -45.9 (3.4) kJ/mol) and formation enthalpy of reaction of SrY0.05Ce0.95O2.975 with water forming Sr(OH)2, CeO2, Y2O3 (DrH (298.15 K) = -85.5 (3.4) kJ/mol). Data obtained by solution calorimetry and additional information on the entropies of different substances have shown that SrY0.05Ce0.95O2.975 is thermodynamically stable with respect to a mixture of SrO, Y2O3, CeO2 and that the reaction of SrY0.05Ce0.95O2.975 with water is thermodynamically favourable.

Nicolas Beaudoin - One of the best experts on this subject based on the ideXlab platform.

  • Zebra rocks: compaction waves create ore deposits
    Scientific Reports, 2017
    Co-Authors: Ulrich Kelka, Manolis Veveakis, Daniel Koehn, Nicolas Beaudoin
    Abstract:

    Nature has a range of distinct mechanisms that cause initially heterogeneous systems to break their symmetry and form patterns. One of these patterns is zebra dolomite that is frequently hosting economically important base metal mineralization. A consistent generic model for the genesis of these periodically banded rocks is still lacking. In this contribution, we present for the first time a fully consistent mathematical model for the genesis of the pattern by coupling the reactive fluid-solid system with hydromechanics. We show that visual banding develops at a given stress and host-rock permeability indicating that the wavelength and occurrence of the pattern may be predictable for natural settings. This finding offers the exciting possibility of estimating conditions of formation of known deposits as well as forecasting potential exploration targets.

O I Anyfrieva - One of the best experts on this subject based on the ideXlab platform.