Evgeny A. Trofimov

Thermodynamic analysis of the Cu-Si-Ni-O system

The liquidus surface of the Cu2O-SiO2-NiO ternary phase diagram is constructed. It is shown that the peritectic reactions occur in the ternary diagram; due to them, a the existence region of nickel olivine Ni2SiO4 with oxide melt manifests itself. A solubility surface of components in the metal of the Cu-Si-Ni-O system for a temperature of 1200°C is constructed.

Thermodynamic description of the interaction processes in the Cu–Ce–O system in the temperature range 1100–1300°C

A thermodynamic simulation and an experimental study of the interaction between cerium and oxygen in liquid copper have been performed. The thermodynamic analysis of the interaction processes in the Cu–Ce–O system is carried out using the technique of constructing the surface of solubility of components in a metal in the temperature range 1100–1300°C. As a result of simulation, data on changes in the Gibbs energy ΔGT° and the equilibrium constants of formation of cerium oxides Ce2O3 and CeO2 from the components of a copper-based metallic melt are obtained. The first-order interaction parameters (according to Wagner) of cerium and oxygen dissolved in liquid copper, namely, eCeCe, eOCe, and eCeO, are evaluated. Experimental studies of the Cu–Ce–O system have been performed. The morphological features, the size, and the composition of nonmetallic inclusions formed as a result of interaction in the Cu–Ce–O system are studied using scanning electron microscopy and electron-probe microanalysis.

Thermodynamic simulation and an experimental study of the possibility of synthesizing hardened Cu–Zr–O alloys

The conditions of formation of hardened Cu–Zr–O alloys are determined theoretically and experimentally. Thermodynamic analysis of the possibility of formation of zirconium oxide in a liquid metal is performed by constructing the surface of component solubility in a metal melt. Disperse zirconium oxide inclusions in samples are detected by scanning electron microscopy and electron-probe microanalysis. The hardness and the electrical conductivity of experimental samples are measured in the as-cast state and after cold deformation. Hardness HV 133 is reached in cold-deformed samples containing 0.05 wt % Zr without heat treatment. The results obtained can be used to create a process for the formation of bulk composite materials based on copper and copper alloys.

Thermodynamic Assessment of the Na-Cu and Na-K Binary Systems

The Na–Cu and Na–K systems present a big interest for the study due to the use of liquid sodium and melt of sodium and potassium in the nuclear industry as a coolant in nuclear reactors. In the present work, thermodynamic modeling of phase equilibria in the Na–Cu and Na–K systems is carried out, based on the available published experimental data. This modeling was done using the “FactSage” software package (version 7.0). The set of Redlich–Kister equation parameters was obtained, that allows to describe the dependence of Gibbs energy from composition and temperature for solutions that can be formed in the studied systems. Phase diagrams (T–x diagrams) of the investigated systems were calculated.

Thermodynamic Simulation of the Phase Diagram of the Cu2O–Na2O–K2O System

Thermodynamic simulation of phase equilibria is carried out, allowing us to calculate the liquidus lines for the phase diagrams of the Cu2O–Na2O, Cu2O–K2O, and K2O–Na2O oxide binary systems, and also the liquidus surface of the Cu2O–Na2O–K2O ternary system. In the course of the work, the values of the model parameters used to calculate the activity of the oxide melts of the investigated systems are determined. The values of the activity of copper oxide and sodium oxide in the Cu2O–Na2O system for a temperature of 1250°C are calculated. The activity data are characterized by negative deviations from Raoult’s law. During the simulation, the enthalpy and entropy of the formation of a KNaO compound from the liquid components are estimated. According to the calculations, the liquidus surface of the phase diagram of the Cu2O–Na2O–K2O ternary system has two points of invariant equilibria.

Experimental Study and Thermodynamic Modeling of Phase Equilibria in BaO-Fe2O3 System

This paper presents the results of the synthesis of compounds of BaO-Fe2O3 system and the results of the study of nature and the melting temperatures of the resulting compounds. Based on the analysis of published data, as well as the results of our studies the systematization of information on the BaO-Fe2O3 system was conducted and an updated phase diagram of this system was proposed.