MAGNETIC-PROPERTIES OF FE-SI ALLOYS SINTE RED IN HIGH-VACUUM

Magnetic properties of Fe-Si alloys which are predominantly sintered i n hydrogen or in vacuum are affected by many powder metallurgical fact ors and show therefore considerable scattering. In this paper the soft magnetic properties of Fe-Si alloys prepared on the basis of air atom ized 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 degrees C for 2 and 4 h in high vacuum (133.3 . 10(-5) Pa, 10(-5) mm Kg). The sinteri ng in the high vacuum was attended with a high sintering and alloying activity of the system from the lowest applied temperature as a conseq uence of dissociation of surface oxides on Si and Fel The relative sam ples density of 94 to 98%, electrical resistivity of 0.51 to 0.96 Omeg a m and coercivity force of 0.8 to 0.29 A.cm(-1) were reached. Formati on of the eutectics was not observed at the temperatures above 1200 de grees C and as well as the effects of liquid phase sintering. The appl ied sintering conditions are acceptable also for the industrial use.