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.