PHASE DIAGRAM OF THE PB-MNSE SYSTEM

Methods of physical and chemical analysis (DTA, MSA, RFA, as well as the definition of microhardness and density) studied the phase equilibrium in the system Pb-MnSe and built its state diagram. It is established that the Pb-MnSe system is a quasi-binary cross-section of the triple system Mn-Pb-Se and is of the eutectic type. The components Pb and MnSe form between the degenerate eutectic composition, which corresponds to 3 mol. % MnSe and melts at 310 ° C. It was found that solid solutions on the basis of MnSe in the system at room temperature reach 3.5 mol. % Pb, and solid solutions on the basis of Pb is practically not installed.

RESEARCH IN THE FIELD OF GLASS FORMATION IN THE ASS-ERS SYSTEM

In order to determine the region of glass formation between the AsS and ErS compounds, we studied the methods of physicochemical analysis: differential thermal (DTA), X-ray phase (XRD), microstructural (MCA), as well as by measuring microhardness and density. The eutectic composition between the AsS and ErS compounds is 10 mol. % ErS and temperature 280oC. At a cooling rate v = 102 K / min, the glass transition region based on AsS reaches 10 mol. % ErS. Some physicochemical properties of alloys from the region of glass formation have been investigated. The area of homogeneity based on AsS reaches up to 1.5 mol. % ErS.

INVESTIGATION OF THE POSSIBILITY OF USING THEORETICAL MODELING METHODS TO DETERMINE THE EUTECTIC COMPOSITION OF BINARY ALLOYS

Рассмотрена возможность поиска эвтектического состава бинарных сплавов различными методами теоретическую математического моделирования. Проведена оценка применимости для этих целей методов Шредера-Ле-Шателье, Кордеса, Эпстейна-Хоуленда, А.В. Суворова на примере сплавов Cd-Bi и Sn-Bi. The possibility of searching for the eutectic composition of binary alloys by various methods of theoretical mathematical modeling is considered. An assessment of the applicability for these purposes of the methods of Schroeder-Le-Chatelier, Cordes, Epstein-Howland, A.V. Suvorov on the example of alloys Cd-Bi and Sn-Bi.

Possibilities of Exploiting Kinetic Control in the Continuous Fractional Crystallization of Diastereomeric Mixtures

For rapid and kinetic control-influenced resolutions, it is advisable to choose a resolving agent with the highest possible eutectic composition (eeEuResAg). It may also be advantageous to add the crystalline resolving agent directly to the solution of the racemic compound. In addition, the use of a quasi-racemic resolving agent or amphoteric resolving agent can provide kinetic resolution. In some cases, the continuous fractional crystallization of diastereomeric salts requires the salt of the resolving agent (Ca2+, Na+, etc.) or other achiral additives (thiourea) that cause rapid crystallization and provide high diastereomeric purity. A further advantage may be the sequential use of the same resolving agent that is capable of forming crystalline diastereomers with both enantiomers when using kinetic control (tandem resolution).