Study On Mid-Frequency Magnetic Pulsing Effects And Performance Of HITPERM Nano Alloy

The new kind of nanocrystalline (FeCo) MBCu (brand name HITPERM) magnetic alloys which was developed by Willard.etc in the basis of NANOPERM, because the frequency response fast, high temperature induction intensity, it has an important potential applications in the high temperature environment and power electronics device. In addition, usually, amorphous alloy only acquired the excellent soft magnetic properties after annealing, but after annealing, it is almost embrittlement, which seriously restrict the development of amorphous application, nanocrystalline magnetic alloys. So to explore a more effective means of amorphous-nanocrystalline is especially important. For this reason, we put forward the magnetic pulse nano crystallization method.This article chooses (Fe1-xCox)86Hf7B6Cu1(x=0.4) amorphous alloy as experimental samples. The preparation process of the first for:chemical composition design, and then smelt the mother alloy with vacuum arc smelting furnace, finally, melt out (Fe1-xCox)86Hf7B6Cu1(x=0.4) alloy with single-roller urgent cold method. The strip’s thickness is about20μm, and width is about2μm.Using the X-ray diffraction analysis, transmission electron microscope, strip r spetrum methods to analyzed the alloy strip and the results show that alloy strip testing of X-ray diffraction pattern performance for a amorphous pack for completely amorphous. Transmission electron microscopy analysis shows that the quenching state alloy strip the diffraction ring for the wide of the overflowing of scattered rings, and was even density matrix, which can be lining judgment system of alloy strip for amorphous. Mossbauer spectrum (MS) analysis indicated the as-quenched alloy presented a typical broadened and overlapped sextet, and the second and fifth peaks were higher than the first and the sixth peaks obviously, which confinned amorphous state. Disposed the amorphous thin belt with mid-frequency magnetic pulsing, the parameters of pulse magnetic field is:pulse frequency:500～2000Hz,pulse field:250Oe, processing time:10min. Then studied the effect of mid-frequency magnetic pulsing of (Fe1-xCox)86Hf7B6Cu1(x=0.4) amorphous alloy with XRD,TEM,MS.Research shows that,mid-frequency magnetic pulsing of amorphous alloy can lead to sample crystallization at room temperature And the crystallization volume fraction is the largest, was33.145%at the processing condition of f=2000Hz, H=250Oe,t=10min.Finally, measuring of (Fe1-xCox)86Hf7B6Cu1(x=0.4) amorphous’thermal stability and soft magnetic properties with DTA and VSM before and after magnetic pulse processing samples,found in f=2000Hz、H=250Oe、t=10min, the crystallization activation energy was by293.3kJ/mol to303.6kJ/mol compare to the quenching state; In the processing condition of f=1500Hz,=250Oe,t=10min, The comprehensive soft magnetic properties is best, coercive force is0.57318G, Saturation magnetization strength is153.80emu/g,Compared with the quenching state of amorphous alloy coercive force for0.66512G, saturation magnetization strength for141.77emu/G have certain of optimization.it can be seen by above, sample amorphous strip has certain optimization with its thermal stability and soft magnetic performance before and after intermediate frequency magnetic pulse, in some degree are at the purpose of this study.