Abstract
Magnetic properties of Fe-Si alloys which are predominantly sintered in hydrogen or in vacuum are affected by many powder metallurgical factors and show therefore considerable scattering. In this paper the soft magnetic properties of Fe-Si alloys prepared on the basis of air atomized iron powder RZ with addition of Si in the form of ferrosilicon in amounts of 2,5 to 6,0% are given. The samples compacted at 300 to 800 MPa were sintered at the temperatures of 900 to 1300 °C for 2 and 4 h in high vacuum (133.3 . 10^-5 Pa, 10^-5 mm Hg). The sintering in the high vacuum was attended with a high sintering and alloying activity of the system from the lowest applied temperature as a consequence of dissociation of surface oxides on Si and Fe. The relative samples density of 94 to 98%, electrical resistivity of 0.51 to 0.96 µΩm and coercivity force of 0.8 to 0.29 A.cm^-1 were reached. Formation of the eutectics was not observed at the temperatures above 1200 °C and as well as the effects of liquid phase sintering. The applied sintering conditions are acceptable also for the industrial use.

Key words
magnetic properties, Fe-Si alloys, powder metallurgical factors

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