[en] X-ray and microstructural analysis methods were used to study the possibility of cationic nonstoichiometry in intermediate phases of the ferroperovskite--ferrogarnet type of the Eu₂O₃--Fe₂O₃ system. It is shown that at 1350⁰C europium ferroperovskite has a narrow range of nonstoichiometry in the direction of excess iron oxide. The character of phase changes in the Eu--Fe--O system during changes in Po₂ has been studied; the equilibrium pressure of oxygen on ferrogarnet and magnetite has been calculated, and an equilibrium phase diagram of the type log Po₂ = f(composition) at 1473⁰K has been constructed. The relative stability of europium ferroperovskite and ferrogarnet has been evaluated

[en] The phase equilibria and the thermodynamics of coexisting phases in the Pr--Fe--O system were studied using static and dynamic methods for attaining equilibrium with subsequent annealing and identification of the condensed phases by x-ray analysis. Equilibrium phase diagrams were constructed to define the changes that take place in the Pr--Fe--O system on variation of the partial oxygen pressure, the temperature, and the composition of the initial mixture of oxides. An isothermal cross section at 1300⁰K and equilibrium diagrams of the type Po₂ = f(composition) with T = constant, Po₂ = f(1/T) with one composition parameter fixed and T = f(composition) with P o₂ = constant have been constructed. It was shown in the Pr--Fe--O system that only one ternary compound with perovskite structure, PrFeO₃, is formed, and furthermore, it is stable no matter how high the partial oxygen pressure

[en] This investigation utilized electron-probe x-ray spectral analysis to study the diffusion zone between NiO and ZnO tablets and an Fe₂O₃ tablet during electron beam irradiation; the mutual diffusion coefficients of the metal ions were calculated. The acceleration of diffusion in electronic-thermal processes is produced by radiation-stimulated diffusion processes, whose coefficients are 2-3 orders of magnitude greater than the corresponding coefficients of thermal diffusion. Interaction of metal oxides in electronic-thermal processes is by a countercurrent diffusion mechanism

[en] Diffusion range between NiO, ZnO tablets and Fe₂O₃ tablet occuring at electron beam irradiation is investigated using electron probe X-ray spectral analysis, coefficients of mutual diffusion of metal ions are calculated. In electron-thermal processes the diffusion acceleration is determined by radiation-stimulated diffusion, which coefficients are by 2-3 orders higher, than corresponding coefficients of thermal diffusion. Interaction of metal oxides in electron-thermal processes occurs according to oncoming diffusion mechanism

[en] It is shown that in the Ce--Fe--O system only one ternary compound with a perovskite structure, the orthoferrite CeFeO₃, is formed. The crystallographic properties of cerium ferroperovskite are defined more accurately. The thermodynamics of its oxidation and reduction over a temperature range of 900 to 1200⁰C are studied using the emf method with a solid electrolyte. It is shown that the free energy of cerium orthoferrite formation from the oxides according to the reaction 1/2Ce₂O₃ + 1/2Fe₂O₃ = CeFeO₃, derived from data on the equilibrium oxidation of CeFeO₃, differs very little from the value of ΔG⁰, calculated from the magnitude of the equilibrium pressure of oxygen over the orthoferrite and reduction products coexisting with it. Phase equilibria and the thermodynamics of coexisting phases in the Ce--Fe--O system were investigated. Equilibrium diagrams are constructed which define the character of the changes taking place in the Ce--Fe--O system during changes in partial oxygen pressure, temperature, and composition of the initial oxide mixture. Thus, we have equilibrium diagrams of the type Po₂ = f(composition) with T = constant; Po₂ = f(1/T) with one composition parameter fixed; and T = f(composition) with Po₂ = constant

[en] A study has been made of conditions under which solid solutions are formed of the type of ferrogarnet and ferroperovskite in Eu-Ce-Fe-O and Eu-Pr-Fe-O systems. Regions of their existence have been determined and isothermal phase diagrams of quasi-ternary sections plotted for Eu₃Fe₅O₁₂-Ce₃Fe₅O₁₂-Pr₃Fe₅O₁₂ (1380 deg C) and EuFeO₃-CeFeO₃-PrFeO₃ (1000 deg C). Phase composition and lattice parameters of solid solutions of ferrogarnets are given

[en] Diffusion processes on ferrite-ferrite boundary under the effect of accelerated electron beam are investigated. Diffusional combination of poly- and monocrystals and processes of mutual diffusion of metal ions in the area of contact are considered. It is shown that as a result of electron beam irradiation of monocrystal-polycrystal ferrite couple on ferrite-ferrite boundary radiation-induced diffusion processes of two types take place. First, the process of diffusional joining (welding) of ferrites, which is determined by vacancy diffusion in near the surface region of ferrites. Second, mutual diffusion of metal ions from ferrite with a higher concentration of the metal to ferrite with a lower concentration takes place and coefficients of electron-thermal diffusion are by an order and more higher than the corresponding coefficients of thermal diffusion

[en] Diffusion processes at a ferrite-ferrite boundary under the action of an accelerated-electron beam were investigated. The authors considered the diffusive fusion of single crystals and monocrystals and the processes involved in mutual diffusion of metal ions in the contact zone. It has been shown that radiation-stimulated diffusion processes of two types take place at the ferrite-ferrite boundary on electron-beam irradiation of an MCF-PCF pair. First of all, diffusive fusion (welding) of the ferrites occurs, as a consequence of vacancy diffusion into the near-surface regions of the ferrites. Secondly, there is mutual diffusion of metal ions from the ferrite with greater concentration of a given metal into the ferrite with lower concentration; the coefficients of electronic/thermal diffusion are more than an order of magnitude greater than the corresponding coefficients of thermal diffusion

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