Composition-property Diagrams Research Articles

Thermodynamic Modeling of Reduction of Cerium from Slags of CaO–SiO2–Ce2O3–15Al2O3–8MgO by Calcium Carbide Additives

Thermodynamic modeling of the reduction of cerium from slags of the CaO–SiO2–Ce2O3 system containing 15% Al2O4 and 8% MgO, with aluminum dissolved in the metal together with calcium carbide additives at temperatures of 1550 and 1650°C was performed using the HSC 8.03 Chemistry software package (Outokumpu) based on the simplex lattice planning method used to minimize Gibbs energy. The results of thermodynamic modeling are presented in the form of composition-property diagrams (equilibrium content of cerium in the metal) for temperatures of 1550 and 1650°C. It is shown that the formation of slags within a basicity range of 2–3 containing 1–7% Ce2O3 provides an equilibrium concentration of cerium in the metal varying from 1 to 7 ppm at a temperature of 1550°C. The displacement of slags in the area of increased basicity (up to 3–5) is accompanied by an increase in the equilibrium concentration of cerium in the metal up to 7–23 ppm with a content of 3–7% Ce2O3 and as a consequence an increase in the efficiency of the process of cerium reduction. At a temperature of 1650°C, the equilibrium concentration of cerium in the metal within the basicity range of 2–3 and having a Ce2O3 content of 1–7% varies from 2 to 12 ppm. The displacement of slags in the area of increased basicity (up to 3–5) is accompanied by an increase in the equilibrium concentration of cerium in the metal to 7–33 ppm with a Ce2O3 content of 3–7%. The positive influence of the temperature factor basicity of slags and the content of cerium oxide on the process of its reduction is qualitatively explained from the standpoint of the formation of the phase composition of the slags of the studied oxide system and the thermodynamics of chemical reactions of reduction of cerium with aluminum dissolved in the metal, as well as with aluminum dissolved in the metal together with calcium carbide additives.

Influence of basicity and boron oxide content in slags of CaO-SiO<sub>2</sub>-B<sub>2</sub>O<sub>3</sub>-Al<sub2</sub>O<sub>3</sub> system on solubility of periclase-carbon refractories

To ensure a low content of sulfur in steel, desulphurization of it in steel ladles is used. To form liquid-movable high-basicity slags with high refining properties, boron oxide is often used instead of fluorspar, the effect of which on the resistance of the refractory lining of steel ladles has not been sufficiently studied and requires detailed theoretical and experimental studies. Results of experimental studies of the influence of the basicity and content of boron oxide in the slags of the CaO-SiO 2 -B 2 O 3 -Al 2 O 3 system on periclase-carbon refractories solubility presented. The studies were carried out using the simplex-lattice planning method. The results of mathematical modeling are presented in the form of a composition-property diagram (solubility of periclase-carbon refractories). Analysis of the experimental data shown in the diagram provided new information about the influence of basicity and boron oxide content in the slags of the CaO-SiO 2 -B 2 O 3 system containing 15% Al2O3 on the solubility of periclase-carbon refractories. It was found that slags formed in the basicity region 2-3, containing 4-6% B 2 O 3 , affect quite aggressively the periclase-carbon refractories. The degree of wear of the refractory sample varies within limits from 20 to 40%. A decrease in the content of B 2 O 3 in the slag down to 1-4% with the same basicity is accompanied by a decrease of the wear degree of the periclase-carbon refractory down to 30% max. Slags of basicity 3-4 at 1-4% B 2 O 3 are characterized by a relatively low aggressive slag effect on the periclase-carbon refractory. The wear degree of periclase-carbon refractory is reduced to 8-12% and practically does not reach 15%. The displacement of slags basicity to the area of increased basicity up to 5 does not lead to a significant reduction in the aggressive impact of slag on the refractory. The degree of wear of the refractory sample varies within 6-10% at the content of 1-4%B 2 O 3 and increases to 12% at 4-6 % B 2 O 3 .

Effective modern methods of protecting metal road structures from corrosion

In the article the ways of protection of barrier road constructions from various external influences which cause development of irreversible corrosion processes are considered. The author studied modern methods of action on metal for corrosion protection and chose the most effective of them: a method of directly affecting the metal structures themselves. This method was studied in more detail in the framework of the experiment. As a result, the article describes the experiment of using a three-layer polymer coating, which includes a thermally activated primer, an elastomeric thermoplastic layer with a spatial structure, and a strong outer polyolefin layer. As a result of the experiment, the ratios of the ingredients for obtaining samples of the treated metal having the best parameters of corrosion resistance, elasticity, and strength were revealed. The author constructed a regression equation describing the main properties of the protective polymer coating using the simplex-lattice planning method in the composition-property diagrams.

Synthesis of pigments in Fe2O3-Al2O3-CoO by co-precipitation method

PurposeThe purpose of this work is to study the patterns of pigment colour formation and to develop metal compositions for obtaining spinels using the precipitation and heat treatment methods.Design/methodology/approachPrecursor materials were prepared using co-precipitation method. Phase composition of pigments were determined by X-ray diffraction. Colour of pigments was determined spectrophotometry. Modelling of colour formation was performed using simplex method. Planning in the future to carry out full synthesis of pigments of blue, red and yellow colours.FindingsThe paper deals with the results of theoretical and experimental research on the synthesis pigments of blue, red and yellow colours based on Fe-Co-Al-O spinel. The influence of the chromophore cation content and the heat treatment temperature on optical and colour characteristics of pigments were studied.Originality/valueThe resulting composition-property diagrams make it possible to evaluate the effect of chromophore cations and heat treatment on the colour formation for Fe2O3-Al2O3-CoO system. Crystal-phase composition of the pigments is installed and its relationship with the optical colour characteristics. That makes it possible carry out targeted synthesis of pigments blue, red and yellow colours in further. The phase composition of pigments and its relationship with optical and colour properties has been established thus enabling the directed synthesis of blue, red and yellow pigments.

Phase composition, structure and properties of thin films based on the double oxide system ZrO2–GeO2

The phase composition, structure and properties of ZrO2–GeO2 thin films obtained by the sol-gel method from the film-forming solutions based on zirconium oxochloride ZrOCl2∙8H2O, germanium tetrachloride and ethyl alcohol are studied. The physical-chemical properties of the films obtained as functions of their composition are determined and the composition–property diagram are constructed.

Analyzing the composition-property diagrams of multicomponent liquid mixtures

We consider the local regularities of the composition-intensive/specific property diagrams of multicomponent mixtures in which composition is a scalar function of a vector argument. A topographical method used in differential geometry is used to produce one-dimensional, two-dimensional, and three-dimensional scalar fields. The scalar field gradient is used to study the composition-property diagrams of five-component mixtures (producing four-dimensional scalar fields).

Structural coordinates of a solution in physicochemical analysis of water-salt systems

In physicochemical analysis of water-salt systems, an approach has been developed in which additional coordinates are introduced into the composition-property diagram of a solution and/or the composition solubility diagram of a salt. These coordinates are determined by solvation interactions and structural changes of aqueous, nonaqueous, and mixed solutions. The trends in the diagrams found in this way are of general character and establish relationships between molecular and macroscopic properties that determine homogeneous and heterogeneous equilibria and phase separation processes. This contributes to the understanding of the nature of the solubility diagram and makes possible prediction of its character.

Kurnakov’s doctrine of physicochemical analysis and the study of aluminum and magnesium alloys at the Baikov Institute of Metallurgy and Materials Science

A brief review is made of the studies of phase diagrams and composition-property diagrams of aluminum and magnesium alloys at the Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Moscow, Russia, in accordance with Academician Kurnakov’s doctrine. The general direction of the studies and the discovered laws are noted.

Modification of high-density polyethylene with binary mixtures of ɛ-caprolactone and ɛ-caprolactam

Modification of high-density polyethylene with binary mixtures of ɛ-caprolactone and ɛ-caprolactam was performed. The composition-property diagrams reflecting the dependences of the physicomechanical, rheological, and optical properties of the resulting polymeric compounds on the content of modifying mixture components were constructed, and the thermal oxidative degradation of the blend samples was studied. Based on the results obtained, the optimal modifier concentrations were suggested.

Hydrolysis of titanium(IV) in the TiO2-SiO2-H2SO4-H2O system during the preparation of a titanium silicate pigment

The hydrolysis of titanium(IV) sulfate during boiling in the presence of silica gel particles is considered. The scenario of solid-phase formation involves the sedimentation of hydrated titanium(IV) onto reactive silica gel particles; and individual phases of silicon(IV) and titanium(IV) hydroxides are formed. The quantitative ratio between the phases of the hydrated composition dictates the properties of its thermolysis products. Composition-property diagrams are plotted to determine the optimum parameters at which the titanium silicate product has high pigment properties.

TYPES OF INORGANIC FLUOROCARBON POLYMER MATERIALS AND STRUCTURE{PROPERTY CORRELATION PROBLEMS

The paper reviews published data on the structure and composition of two large classes of inorganic polymer fluorocarbon materials (IP FCMs), including high‐temperature (HT) and low‐temperature (LT) modifications of graphite fluorides and fluorographite‐like compounds CFx (x = 0.5 – 1.12$) and CF1+y (y = 0.08 – 1.33$) and intercalated fluorographite compounds (IFGCs) based on CxF (x < 2) matrices. According to X‐ray diffraction data, C1s and F1s X‐ray photoelectron spectroscopy (XPS), 13C and 19F NMR, CKα and FKα X‐ray spectroscopy, and IR and Raman spectroscopy, as well as MNDO calculations, the structure of monolayers and the properties of IP FCMs of C2F – CF1+y composition depend on the combination of C(sp3) – F fragments bonded to the sp2 fragments of the starting carbon matrices. The structure of high‐temperature CF1+y is specified by the presence of structurally isolated external and internal C(sp3)F2 groups located on the boundaries of C(sp3) – F skeleton monolayers and in the holes of their nanostructures, respectively. The enthalpy of formation of HT FCMs does not depend on the type of starting carbon material and is linearly proportional to the F/C atomic ratio; C(sp3)F and C(sp3)F2 groups are chemically indistinguishable in HT FCMs. Six models for the structure of C2F and C4F monolayers in LT FCMs are considered. The best agreement with spectroscopy and MNDO data is obtained using modified Yudanov–Gornostaev's model for C2F, in which alternating rows of graphitelike sp2 carbon fragments coexist with rows of bonded perfluorocyclohexane sp3 cells. For low‐temperature C24F–C2F, electric conductivity and C1s and F1s XPS data are generalized and composition–property diagrams are constructed. In this case, the conductivity, C1s and F1s XPS, and the interplanar distances in monolayers are explained using the concept of planarity of CxF monolayers and the ensuing ideas of semi‐ionic and semicovalent C=F bonds. For C4F · yA–C2F · zA compositions, 13C and 19F NMR data, C1s and F1s XPS, and IR data are accounted for by the predominant sp3 nature of the structure‐forming C=F bonds.

Influence of Chemical and Phase Equilibria on the Medium-Range Order and Physicochemical Properties of Chalcogenide Glasses1

The problem associated with the influence of chemical and phase equilibria in melts on the properties of formed glasses is analyzed experimentally and theoretically by the example of chalcogenide glasses prone to glass formation. It is proved that inorganic glasses should be treated as microinhomogeneous systems formed by a set of nanometer-sized pseudophases that differ in character. The equivalentometry method has revealed that, in inorganic glasses, there exist at least two types of the pseudophases which have different chemical compositions and are responsible for microinhomogeneous structure of vitreous materials. It is established that the pseudophases in glasses are fragments composed of elementary substances and are also stable and metastable compounds. The concept of a variable number of components in vitrifying melts is introduced for the first time. This concept and the eutectoidal model of the vitreous state of matter allow one to reveal the types of chemical and phase equilibria whose freezing in glasses results in the formation of a set of the pseudophases responsible for glass microinhomogeneity. The regularities revealed make it possible to put forward the principles of analysis of composition–property diagrams for vitreous systems.

Optimizing the properties of the solid electrolytes of the systems ?zro2-oxides of rare-earth elements (ree)? using the simplex-grid planning method

Using the method of simplex-grid experimental planning, the properties of the ZrO2-based solid electrolytes were optimized. The composition-property diagrams were plotted in a limited range of compositions. The relationship between the stabilizing additives facilitating the production of solid electrolytes possessing a high electrical conductivity and its stability during the process of isothermal dwells was established.

Use of the method of experiment planning to investigate the mechanical properties of manganese steels

1. Composition-property diagrams obtained in using the simplex-lattice method of experiment planning for manganese steels on varying the elements within the range from 6.0 to 8.0% of Mn and 0.05–0.60% of C make it possible to optimize steel compositions with respect to mechanical properties.

Properties of multicomponent polymers systems

In order to design materials having different mechanical properties combined with a permittivity of 2.2–2.6 and tg δ=2·10−4-4.10−4 at 20±1° C and 106 Hz, it is possible to use compositions consisting of polystyrene, polyisobutylene and polyethylene. Projections of the three-dimensional triangular composition-property diagrams are presented for selecting the composition corresponding to spcified properties (hardness at 20 and 50° C and breaking stress and elongation).

Relationship between the state diagram and composition-property diagrams of the In-Sn system

Relationship between the state diagram and composition-property diagrams of the In-Sn system

Physicomechanical properties of elastomers in binary and ternary systems

A study was made of the physicomechanical and thermophysical properties of elastomers in binary and ternary systems consisting of polyamide, polyvinyl chloride, and rubber in various proportions. Binary and ternary systems with optimal physical and mechanical properties were selected from the composition-property diagrams for engineering applications. It was found that at a given ratio of polyvinyl chloride and SKN-40 rubber there is a nonmonotonic change in the physicochemical properties of films caused, apparently, by chemical interaction. It was shown that the mechanical properties of polyamide can be stabilized against thermal aging by blending with binary systems.

The principles of construction of a machine language for physico-chemical analysis

C ontemporary chemistry deals not only with individual substances, but also with systems of substances (alloys, solutions, etc.). A graphical method, based on the construction of composition-property graphs, is widely used to describe the vast amount of material accumulated in the study of such systems. Operations using graphs of this kind are basically different from those using linear and structural chemical formulae, and their combinations, the equations of chemical reactions. In 1925, it was stated by Kurnakov [1] that graphical methods of representing physical and chemical processes in equilibrium systems are in point of fact the basic elements of an international chemical geometrized language, analogous to, but more general than, the language of chemical formulae, including not only separate substances but also their combinations and all chemical changes in general. According to Kurnakov “the composition-property diagram is a graphical representation of the complex function which defines the relation between the composition of homogeneous bodies or phases formed in the system and their properties.”