Electrochemical Reducing of Terbium and Holmium Ions in the Sodium and Potassium Chlorides Melt with Equimolar Composition

Interest to rare-earth metals (REM) and their alloys is due to the possibility of using them for the creation of new materials need for modern technology. For instance, REM as alloying components allows for preparation of material with special magnetic properties. A promising method for forming such coating is the surface treatment of metals. This process has an electrochemical character as such for the organization of technology the knowledge of kinetics and mechanism of these processes is important. Despite significant interest in rare-earth metals, these issues are not well described in the literature. In order to choose an adequate mathematical model for calculation of kinetic primers, preliminary experiments that allow evaluating the reversibility of the electrode process have been conducted. Based on that, it was concluded that cathodic reduction of terbium and holmium ions in equimolar NaCl-KCl melt is irreversible. By means of voltammetric analysis, kinetic parameters (transfer coefficients, heterogeneous constants of charge transfer rate) of terbium and holmium electroreduction in equimolar NaCl-KCl melt were determined. The experiment was conducted in a three-electrode cell under a purified argon atmosphere. A dependency of kinetic parameters on the concentration of terbium and holmium chlorides wt (%): 1, 3, 5, 7, 10, was determined. The experiment was conducted in 1073–1173K temperature range. Values of kinetic parameters increase with temperature but decrease with the increase of REM chloride. Based on obtained data, it was found that electroreduction of chloride complexes LnCl63– (Ln–Tb, Ho) in equimolar NaCl-KCl melt is irreversible in the studied range of temperatures and REM concentrations. In summary of experimental data, in range of temperature and rare-earth chloride concentration, and assumption was made that reduction of terbium and holmium ions occurs in two stages. The process includes the preceding stage of complex dissociation. A mechanism of LnCl63– complex reduction in the mentioned melt is proposed. The obtained results are in agreement with literate data for analogues systems

Determination Of Formation Regimes For Bilayer Cobalt Dysprosium Intermetalic Surface Alloy

High tech industrial fields on modern development stage are in need of construction materials with an optimal ratio of volume and surface properties, along with low cost of material itself. As evidenced by studies, in order to give a set complex of properties to a workpiece that operates under specific conditions, it is often sufficient to only modify its surface area. Over the course of studies, by means of gravimetric, influence of technological parameters (temperature and time samples are kept in the melt) on specific mass change of cobalt samples, that act as substrate, during electroless diffusive saturation with dysprosium in eutectic melt of lithium and potassium chlorides have been studied. A mathematical dependency was established for specific mass change of cobalt samples on time spent in melt for temperature range of 873–973 K. Composition of intermetallic coats obtained on surface of cobalt samples was studied means of EDX and SEM analyses. It was discovered, that for chosen temperature range, diffusion layers formed on surface of cobalt samples consists of two structural zones that correspond to Co-Dy and Cp2Dy phases

Electronic Social Networks as Supporting Means of Educational Process in Higher Education Institutions

Given research describes experience of electronic social networks use in educational practices. It was determined that electronic social networks can be a powerful tool for support of educational process in higher education institutions, namely to support study of different disciplines. There are main advantages of electronic social networks use for education: universal accessibility and free of charge; possibility of instant messaging and multimedia data; user-friendly intuitive interface; ability to search data and information; availability of event scheduling, invitations, reminder settings; support for synchronous and asynchronous communication between network members; access from different devices. It is emphasized that one of the main advantages of electronic social networks is receipt of quick feedback and convenience of their tools and services. Nowadays, it is important to include network educational interaction in existing models of study organization. It is advisable to use electronic social networks to manage educational process in higher education institution. Efficiency of electronic social networks use depends on intensity and need for their use in educational system management for implementation of organizational, educational, psychological and pedagogical functions and ensuring universal communication with subjects of educational process. Expediency of electronic social networks use to carry out research work at university is described. Electronic social networks are convenient tool to conduct surveys and questionnaires, to create thematic groups for specific issue discussion. Also it is possible to interact with researchers from different countries, share experiences and disseminate research findings, invite those who wish to participate in various scientific activities using these networks