Abstract. The mixture of 20.0 wt% Fe and 80.0 wt% BaTiO₃ powders was found to consist of a BaTiO₃ matrix and composite particles comprising Fe cores and BaTiO₃ shells. During the grinding of this mixture, several processes occur, such as pulverization of the particles of both powders; changes in the size, morphology and composition of aggregates, crushing of crystal grains, increase in the density of chaotically distributed dislocations; growth of internal microstrains; rise in the residual stress; decrease in the amount of crystalline and increase in the amount of amorphous phases, as well as oxidation of Fe into its oxides FeO, Fe₃O₄ and Fe₂O₃. These changes in chemical composition, morphology and microstructure substantially affect the magnetization of the pressed powder mixture. With increasing the grinding time from 0 to 90 min, the increase in magnetization is dominantly affected by crushing of Fe crystal grains. The decrease in magnetization during grinding from 90 to 120 min is caused by the decrease in the amount of metallic Fe by oxidation to FeO and increase in both the density of chaotically distributed dislocations and internal microstrains. Formation of Fe₃O₄ and Fe₂O₃ oxides has a prevailing effect on the increase in magnetization when grinding for longer than 130 min. Chemical and microstructural changes in the mixture of powders of 20.0 wt% Fe and 80.0 wt% BaTiO₃ during heating affect the magnetization of cooled samples at 22°C. The powder is thermally stable up to 330°C. The magnetization of samples cooled to 22°C declines with increasing annealing temperature above 330°C. This decrease is caused by both the oxidation of Fe to FeO and formation of larger crystalline grains of Fe. The magnetization of samples heated up to 250°C remains unchanged. At higher temperatures, with increasing the temperature of the sample, its magnetization declines as a result of the transition of directed domains to a chaotic state caused by the effect of thermal energy, formation of larger crystal grains and oxidation of Fe into FeO.

Key words: Grinding, pressing, magnetic, BaTiO3 microstructure.