CHARACTERIZATION SUBSOLIDUS SYSTEM STRUCTURE CaO - Al2O3 - CoO – NiO

Abstract

The paper presents the results of calculations characterizing the elements of the subsolidus structure of the CaO– Al2O3 – CoO – NiO system, which is promising for the production of modified aluminous cements and heterophase materials with a complex of unique properties. Insufficient information about the structure of the four-component phase diagram of a certain multicomponent system makes it difficult to obtain such materials. To predict the phase composition of materials, theoretical studies of the structure of the system were carried out. An analysis of the features of the coexistence of heterophase combinations was carried out, taking into account geometric-topological and statistical characteristics. The technological risks of predicting the phase composition of materials that arise in certain concentration regions of the system under study are shown. Calculations were carried out over the entire temperature range, both up to the melting point of the ternary oxide compound Ca3CoAl4O10 at 1439 K, and in a higher temperature region. Using known methods, the characteristics of eutectics in some sections of the system under study, which is of interest for the technological design of materials, were calculated. The results of calculations of the characteristics of eutectics show that among the analyzed tetrahedra, the minimum eutectic temperature (1367 K) is observed between the oxides of cobalt, nickel, calcium-cobalt aluminate and calcium monoaluminate, which can be realized for the synthesis of heterophase materials with a high content of Ca3CoAl4O10. Such materials have practical application in various industries: lime production; lime binders; corundum abrasives and refractories; high temperature catalysts; ceramics with special electromagnetic properties.