| Fe-based amorphous alloys and nanocrystalline alloys （e.g., the FINEMET alloy）, whichare obtained by crystallization of the amorphous precursors, is widely concerned with veryexcellent soft magnetic properties. In this thesis, we study the crystallization behavior and softmagnetic properties of the FeSiBMoCrCuP amorphous alloy. Meanwhile, the influences of thechanges in concertrations of B for amorphous crystallization behaviors are discussed and theinfluences of structure and magnetic properties of the alloy also been studied when add the rightamout of rare earth Y.The alloy ingots were prepared by medium frequency induction melting furnace underatmospheric conditions. A single-roller melt spinning method was employed to prepareFe81-xSi13BxCu1Mo2Cr1P2and Fe71.4-ySi13B9.6Cu1Mo2Cr1P2Yy（y=50ppm，77ppm） amorphousribbons. The microstructure and magnetic properties of the amorphous and annealed alloysribbons were investigated by X-ray diffractmeter （XRD）, differential scanning calorimetry（DSC）, HT35core measuring instrument and TYU-2000M soft magnetic propertiesmeasurement instrument.The crystallization behavior and soft magnetic properties of the nanocrystallineFe71.4Si13B9.6Cu1Mo2Cr1P2alloy are investigated. The nanocrystalline alloys are obtained byannealing of the amorphous precursors at different annealing temperatures. The results indicatethat the whole substitution of Mo and Cr for Nb of the FINEMET alloy also shows the goodsoft magnetic properties, especially to improve the initial magnetic permeability. By XRDresults show that the alloy sample under quenching state is completely amorphous. Afterisothermal annealing at525°C for30min show the best soft magnetic properties:Bm=1.04T（H=5.165A/m），μ0=130000Gs/Oe，when the frequency is50Hz，Hc=1.48A/m，Ps=0.012W/kg；when the frequency is50Hz， Hc=3.14A/m，Ps=2.133W/kg。The influence of the B content change on the soft magnetic properties and structure of theFe81-xSi13BxCu1Mo2Cr1P2（x=8.69.6） alloy are investigated. The results shows that under thecondition of B≥9.5can be completely amorphous and increased content of B reduce the nanograin size. When increasing the content of B of the alloy, the initial temperature Tx1of the firstcrystalliziation peak is decreased. On the other hand, the temperature range between the firstcrystalliziation peak and the second crystalliziation peak is reduced. Magnetic detection resultsshow the magnetic permeability μ is improved with increasing B content. The best softmagnetic properties are obtained as the contents of B reach9.5%and9.6%.The influence on the preparation and performance of adding the rare earth Y to theFe71.4Si13B9.6Cu1Mo2Cr1P2alloy is studied. The results indicate that a small addition of rare earth Y can purify the liquid steel, improve the alloy’s liquidity which is conducive to thepreparation of amorphous strip. With the addition of rare earth Y to the alloy, the best annealingtemperature is reduced for1015°C, the initial magnetic permeability is decreased and themaximum permeability is increased. Higher Bsis obtained for the addition of rare earth Y; theBs reached1.192T （H=5.165A/m） when Y=77ppm. However, the addition of Y is increasedcoercive force （Hc） and core loss （Ps）. |
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