STRUCTURAL-CHANGES IN THE SENDUST-TYPE ALLOYS UPON RAPID SOLIDIFICATION BY MELT-SPINNING AND LASER TREATMENT

Being the most hard and wear resistant soft magnetic material, sendust (Fe-9.5 wt.% Si-5.5 wt.% Al, VHN = 5000 MPa)(1) is the main metallic material for the cores of magnetic heads in video tape recorders. An a ddition of carbide or boride phase in this alloy can hardened it to 55 00-6250 MPa. and improve its magnetic properties at megahertz frequenc ies. In this work, the effect of rapid solidification by melt spinning and laser treatment on the structure and hardness of the sendust-type alloys containing an enhanced (up to 3%) concentration of carbide or boride was studied. The treatment leads to the refinement of the grain structure of all alloys, a decrease in the order parameters of untrea ted alloys, and an increase in their hardness up to VHN = 7550 MPa (tw ofold laser treatment of the alloy with boride). The problems of the t reatment and crystal defects, which require further research, were rev ealed.