Influence of the Elemental Composition and Thermodynamic Background on the Processes of Phase Formation in Solid Solutions of the Triple System NaNbO3 − KNbO3 − BiFeO3

Using conventional ceramic technology, solid solutions (SS) of the system (1 – x)(Na0.5K0.5)NbO3 – xBiFeO3 with x = 0.05, 0.20, 0.55, 0.95 were obtained by solid phase synthesis in two stages. It has been established that the structure of the studied solid solutions critically depends on technological regulations: solid solutions close in composition to (Na0.5K0.5)NbO3 are characterized by the highest sintering temperatures, low relative densities and their discrepancy in trial and experimental samples at one and the same temperature; and those close in composition to BiFeO3 are characterized by low sintering temperatures, high relative densities and practically identical relative densities of trial and experimental samples. Two phase transitions have been identified: (i) in fact the decomposition of SS, takes place in the interval 0.00 < x < 0.05, (ii) transition from the C-phase to the Rh-phase occurs in the interval 0.55 < x < 0.95.