Microstructures and soft magnetic properties of Fe_(73.5)Cu_(1)Nb_(3-x)Si_(13.5)B_(9)Yx(x=0-1.5)alloys

Based on composition of Finemet alloy,structures and soft magnetic properties of Fe_(73.5)Cu_(1)Nb_(3-x)Si_(13.5)B_(9)Yx(x=0,0.5,1.0,1.5)alloys formed by replacing Nb(niobium)by Y(yttrium)were studied in this paper.The research results show that when x=0 or 0.5,rapidly solidified as-cast alloy is Fe amorphous single-phase structure,and Y atoms are dispersed in matrix;when x=1.0 or 1.5,crystalline phase precipitates.Fe_(73.5)Cu_(1)Nb_(3-x)Si_(13.5)B_(9)Yx(x=0,0.5,1.0,1.5)alloys begin to precipitateα-Fe(Si)solid solution phase after crystallization annealing above 480℃,when x=0.5,grain size is 12.6 nm,which shows that Y can replace Nb in small amount and refine grain size.Fe_(73.5)Cu_(1)Nb_(2.5)Si_(13.5)B_(9)Y_(0.5)alloy has excellent soft magnetic properties:μm value is 813.1×10^(3),which is 36%higher than that of Finemet alloy;μi value is 154.6×10^(3),close to that of Finemet alloy,and BS and Hc values are 1.24 T and 0.56 A/m,respectively,better than those of Finemet alloy.In addition,Fe_(73.5)Cu_(1)Nb_(2.5)Si_(13.5)B_(9)Y_(0.5)alloy has excellent soft magnetic properties at high temperature,μe value only reduces by 8.8%at 1 kHz with ambient temperature increased from 30 to150℃,andμe value is 128.02×10^(3)in 150℃,which is 15.74%higher than that of Finemet alloy.

Morphological,electromagnetic and absorbing properties of GR/Fe_(93.5)Si_(3.5)La_(1)Ce_(2) composite powders

In this study,the morphological,electromagnetic and absorbing properties of GR/Fe_(93.5)Si_(3.5)La_(1)Ce_(2) composite powders were systematically investigated.The composite powders was prepared by highenergy ball milling.X-ray diffractometer(XRD) and Raman spectroscopy analyses confirm the presence of α-Fe and graphene in the composite powders.Scanning electron microscopy(SEM) observation shows that the composite powders have a flake morphology.The electromagnetic and absorbing properties of the composite powders were analyzed with a vector network analyzer.When the milling time and graphene content are 12 h and 1 wt%,respectively,the composite powders exhibit the best absorbing property.For 1.0 wt% GR/Fe_(93.5)Si_(3.5)La_(1)Ce_(2) composite at 0.3 GHz,the ε’and ε" are 77.76 and124.73,and the μ’and μ" are 6.09 and 2.83.Its tanδ_(ε),tanδ_(μ) and tanδ reach 0.63,13.80 and 14.43,respectively,which basically increased the tanδ by more than 2 times compared with other composite powders.This indicates that the composite powder has excellent wave absorption performance.Meanwhile,the analysis shows that the loss mechanism of the composite powder is mainly relaxation loss,conduction loss,eddy current loss and natural resonance.Therefore,this composite powder provides a new approach for the development of wave absorbing materials.