Abstract

M. M. Mataev¹, N. O. Myrzakhmetova², Zh. K. Kuanysheva², I. S. Saparbekova², S. M. Bazilbayev², G. A. Doszhanova², G. Medeuova²

DOI : http://dx.doi.org/10.13005/ojc/310153

Abstract. By method of dynamic calorimetry, in the temperature range between 298,15 and 673 K, isobaric heat capacity of polycrystalline ferrites Bі₂СаFe₄O₁₀, BіMgFe₂O_5.5, Bі₂MgFe₄O₁₀ was experimentally studied. Mathematical processing of experimental data made it possible to derive polynomial equation of temperature dependence of ferrites heat capacity for respective temperature ranges, in dependencies C⁰_p~f(T) of ferrite Bі₂СаFe₄O₁₀ a jump was detected in heat capacity at 625 K associated with  phase transitions of type II. The values of the thermodynamic functions C⁰_p(Т), H⁰(T) – Н⁰(298,15), C⁰(T), F^hh(Т) have been calculated. Standard values of thermodynamic functions were determined using the method of ion increments. The results obtained broaden thermodynamic data bank for complex inorganic crystalline compounds.

oxides; ferrites; heat capacity; thermodynamic functions; calorimetry

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