ИСТИНА

Данный проект направлен на комплексное изучение многокомпонентных систем Ag-In-Pd-Sn и Cu-In-Pd-Sn, включающее также термодинамический расчет этих систем и разработку методов формального описания фазовых границ. Это позволит установить области существования интерметаллических фаз в указанных четверных системах, и изучить их свойства; рассчитать фазовые равновесия в широком диапазоне температур и составов, спрогнозировать свойства фаз более сложных (пятикомпонентных) систем. Параметрическое описание конод двухфазных равновесий позволит выбирать сплавы с необходимым составом фаз и их количественном соотношении. Все это расширяет возможности выбора материалов под конкретную задачу.

The transition to advanced technologies for designing and creating new materials is impossible without knowledge of the equilibrium phase diagrams of multicomponent systems, since they contain information on phase transformations and temperature-concentration regions of phase existence that can be realized in alloys or composite materials. Information on phase equilibria allows one to quickly determine the optimal composition of a new material and reliably predict changes in its properties and possible phase transformations during operation. Ternary intermetallic compounds of palladium with tin and indium have proven their effectiveness as catalysts for the process of hydrocarbon hydrogenation. The introduction of silver or copper into these compounds in order to increase the resistance of catalysts to poisoning is promising. Palladium alloys with these metals are widely used in hydrogen energy and in orthopedic dentistry. Regardless of the area of ​​application of the material, when choosing its composition, data on the regions of existence and the crystal structure of the phases realized in it are necessary. The development of new metallic materials is associated with a complication of the composition and is based on knowledge of the state diagrams of multicomponent systems. However, with an increase in the number of components in the system, the material and time costs for establishing the nature of phase equilibria increase many times. Therefore, recently, methods for theoretical construction of phase diagrams of multicomponent systems have been actively developed, including thermodynamic modeling of phase equilibria - the CALPHAD method, as well as a formal analytical description of phase boundaries. The goal of this project is a comprehensive study of the four-component Ag-In-Pd-Sn and Cu-In-Pd-Sn systems, including the experimental establishment of the regions of existence of various phases, their crystal structure and some properties, thermodynamic calculation of these systems using the CALPHAD method and the construction of a parametric description of the conodes of equilibria involving a solid solution based on fcc components. The scientific novelty of the project lies in the fact that for the first time, the solubility limits of p-metals, indium and tin, in a solid solution based on fcc components, as well as the solubility of silver and copper in intermetallic compounds of the In-Pd-Sn system, will be experimentally established. In the process of thermodynamic modeling of the four-component Ag-In-Pd-Sn and Cu-In-Pd-Sn systems, the existing descriptions of boundary ternary systems will be revised in order to use identical Gibbs energies of component formation and unified models of isostructural phases. The obtained parameters of the phase models will allow determining the phase composition and properties of phases in a wide range of temperatures and compositions in the specified quaternary systems, as well as predicting phase equilibria in more complex ones. A method for parametrically describing the equilibria of a solid solution and its coexisting phases will be developed. This approach is based on an analytical description of the concentration dependences of lines or surfaces of the centers of the conodes and the distribution coefficients of the components. This method will allow determining the compositions of the solid solution based on fcc components (Ag, Cu and Pd) and phases in equilibrium with it in the ternary systems Ag–In–Pd, Ag–Pd–Sn, Ag-Cu-In and In–Pd–Sn and the quaternary Ag-In-Pd-Sn and Cu-In-Pd-Sn systems, as well as the quantitative ratio of these phases in an alloy of a given composition. Based on such a description of equilibria, it will be possible to select alloy compositions with the required amount of the strengthening phase.