Investigation Of Elements Additions On The Properties Of FeSiB(PCu) Amorphous/nanocrystalline Soft Magnetic Alloys

Fe-based amorphous/nanocrystalline soft magnetic alloys have excellent magnetic properties,meanwhile, the preparation process of which is simple and with less energy consumption and lowpollution et al. Therefore they have been paid much attention in both fundamental research andindustrial application. In this thesis, the method of element substitution is used to design the alloycomposition. Melt spun ribbons are prepared by single roller melt spinning method followed byannealing. X-ray diffractometer, differential scanning calorimeter, transmission electron microscopeand magnetic property measurement equipments are used to investigate the microstructure, thermalbehaviors, glass forming ability and magnetic properties of the alloy ribbons. The related researchresults of this thesis can be theoretically and experimentally useful for developing nanocrystallinealloys with excellent properties such as good glass forming ability, large crystallization temperatureinterval and good magnetic properties.Based on the Fe78Si9B13 alloy, effects of substitution B by P element are investigated. Theaddition of P decreases the glass forming ability of the alloy system. While the content of P reach upto 6 at.% the amorphous structure can still be obtained. Meanwhile, the addition of P deteriorates thesoft magnetic properties and decreases the crystallization temperature of this alloy system atas-quenched state. For the alloy ribbons annealed at 300 °C for 1 h, the coercivity decreases and thesaturation induction density increases compared with those of as-quenched state. At the annealed statewith the increase content of P, the saturation induction density gradually decreases while thecoercivity decreases to a minimum at 2 at.% of P content and then increases.Based on the Fe81Si4B12P2Cu1 alloy, effects of Cr, Mn, V and Ti substituting for B are investigated.Partial substitution of B by Cr or Mn decreases the glass forming ability of this alloy system, whileproper substitution by V or Ti effectively improves the glass forming ability. With the addition of thefour elements mentioned above, the crystallization temperature intervals are widened. Both V and Tielements in Fe Si BPCu V and Fe Si BPCu Ti alloy ribbons can suppress the grain growth during theprocess of crystallization and thus improve the soft magnetic properties of the annealed alloys.Suitable amount of Ti can increase the volume fraction of α-Fe phase which is beneficial to lower theof the magnetostriction of the nanocrystalline alloys.Based on research results on the process of the crystallization of Fe Si BCu Nb, Fe Si BCu,Fe Si BPCu and Fe Si BPCu Al nanocrystalline alloys, we have also tried to speculate the role of eachelement in the crystallization process and establish a crystallization model of Fe Si BPCu M alloysystem.