High pressure compaction of soft magnetic iron powder

Iron is the most widespread ferromagnetic used in soft magnetic composites. Ferromagnetic powders are usually pressed at relatively high pressure to the required shape before heat treatment. The functional properties of soft magnetic materials and composites strongly depend on the pressing parameters. In this paper, the densification of the pure powder iron was investigated in a wide range of pressure to 2.5 GPa. Correlation of microstructure, density, mechanical and magnetic properties with pressing pressure was studied in detail. Compressibility analysis based on the Equation of state was used for the identification of densification mechanisms. The wider the interval of pressures, the higher the degree of polynomial dependence to describe the densification process. Higher variability of densification processes is associated with changes in the microstructure and porosity. For each shape of the green compact, there is a specific distribution of density and thus also a change in magnetic and electrical properties.