This work presents the electrochemical study of lanthanum and uranium compounds in fused 3LiCl-2KCl eutectic vs. Cl-/Cl-2 reference electrode in the temperature range 723-823 K on liquid gallium-indium eutectic alloy. Thermodynamics and the activity coefficients of lanthanum and uranium were studied. The separation factor of uranium from lanthanum on gallium-indium eutectic alloy was determined. (C) 2014 Elsevier Ltd. All rights reserved.

This work presents the electrochemical study of Cm(III) in fused 3LiCl–2KCl eutectic in the temperature range 723–923K. Transient electrochemical techniques such as cyclic, square wave voltammetries, and chronopotentiometry have been used in order to investigate the reduction mechanism of curium ions up to metal. The results obtained show that the reduction reaction takes place in a single step Cm(III)+3e¯⇒Cm(0). The diffusion coefficient of Cm3+ ions was determined by cyclic voltammetry at different temperatures by applying Berzins–Delahay equation. The validity of the Arrhenius law was also verified and the activation energy for diffusion was found to be 28.21kJmol−1. The apparent standard electrode potential of the redox couple Cm(III)/Cm(0) was found by chronopotentiometry at several temperatures. The thermodynamic properties of curium trichloride have also been calculated.

This work presents the electrochemical study of Cm(III) in fused NaCl–2CsCl eutectic in the temperature range 823–1023K. Transient electrochemical techniques such as cyclic, differential pulse and square wave voltammetry, and chronopotentiometry have been used in order to investigate the reduction mechanism of curium ions up to the metal. The results obtained show that the reduction reaction takes place in a single step Cm(III)+3e¯⇒Cm(0). The diffusion coefficient of [CmCl6]3- complex ions was determined by cyclic voltammetry at different temperatures by applying the Berzins–Delahay equation. The validity of the Arrhenius law was also verified and the activation energy for diffusion was found to be 44.46kJ/mol. The apparent standard electrode potential of the redox couple Cm(III)/Cm(0) was found by chronopotentiometry at several temperatures. The thermodynamic properties of curium trichloride have also been calculated.

This work presents the influence of electrode material nature on the mechanism of cathodic reduction of ytterbium (III) ions in fused NaCl–KCl–CsCl eutectic at the temperature range 723–1073K. Transient electrochemical techniques such as linear sweep, cyclic, semi-integral and square wave voltammetry, and potentiometry at zero current have been used in order to investigate the reduction mechanism of ytterbium ions on inert and active working electrodes, transport parameters and thermodynamics properties of the ytterbium compounds. The influence of the material of working electrode on the mechanism of the cathode process was determined. The results obtained show that the reduction reaction Yb(III)+e¯⇔Yb(II) on W electrode is reversible being controlled by the rate of the mass transfer. The diffusion coefficient of [YbCl6]3- complex ions was calculated at different temperatures and the apparent standard electrode potential of the soluble–soluble redox system Yb3+/Yb2+ was obtained. The reduction reaction of ytterbium (III) ions on Al active electrode was investigated. Al2Yb and Al3Yb alloys are formed during the polarization on the surface of working electrode.

This work presents the electrochemical study of Yb(III) ions in molten alkali metal chlorides in the temperature range 723–1073K. Transient electrochemical techniques such as linear sweep, cyclic and square wave voltammetry, and potentiometry at zero current have been used to investigate the reduction mechanism, transport parameters and thermodynamic properties of the reaction YbCl2+1/2Cl2=YbCl3 The results obtained show that the reduction reaction Yb(III)+e−⇔Yb(II) is reversible being controlled by the rate of the mass transfer. The diffusion coefficient of [YbCl6]3− complex ions has been determined at different temperatures in the fused eutectic LiCl–KCl, the equimolar NaCl–KCl and the CsCl media. The apparent standard potential of the soluble–soluble redox system Yb(III)/Yb(II) has been obtained by cyclic voltammetry. The influence of the nature of the solvent on the electrochemical and thermodynamic properties of ytterbium compounds is discussed.

This paper presents the results of ball indentation tests carried out on specimens of pipeline steels. The loadings of a spherical (D=5 mm) indenter in the range from 147 to 11875 N within absolute temperature range 77-293 K were applied. Then the indentation energy U-f, corresponding to condition HM =sigma(f), where HM and sigma(f) are the Meyer's hardness and the material's critical cleavage fracture stress, was calculated. This energy U-f, is known as IEF (indentation energy to fracture). The comparison of fracture toughness K-IC, and U-f values reveals linear relationships K-IC(U-f) for all steels in all the investigated temperature range. Angle coefficient phi, in these relationships depends on fracture stress in tension S-k, for every steel. For the purposes of non-destructive Sk estimation, the relationship between Sk and Misses stress sigma(i), in the center of impression at the temperature 77 K was established. At last K-Ic, values can be calculated from the single unified equation for all investigated steels. Thus, the method of indirect fracture toughness K-Ic, estimation for pipeline and pressure vessel steels, based on the IEF (Indentation Energy to Fracture) model, is developed and discussed.