Synthesis of novel FeSiBPCCu alloys with high amorphous forming ability and good soft magnetic properties

Abstract Novel Fe 83.3 Si 4 B 8 P 4- x C x Cu 0.7 ( x  = 0–4) alloys were developed with the aim of increasing amorphous forming ability (AFA) without deteriorating the soft magnetic properties. Microstructure analysis revealed that the substitution of C for P inhibited the precipitation of α-Fe phase during the quenching process hence increased the AFA. The critical thickness increased from 18 μm for the alloys with composition of x  = 0 to 43 μm for x  = 4, respectively, owing to the decrease in the melting entropy ( ∆S m ), the approach of eutectic point and micro-alloying effect. Saturation magnetic flux density ( B s ) increased obviously after proper annealing with increasing C substitution due to the increase in volume fraction of α-Fe nanocrystals, while excessive C content leaded larger coercivity ( H c ) but improved the frequency and DC superposition performance. The Fe 83.3 Si 4 B 8 P 2 C 2 Cu 0.7 nanocrystalline alloy was successfully synthesized with high B s of 1.84 T, low H c of 4.8 A/m and high effective permeability (μ e ) of 13,540. The combination of high B s and high resistance to DC bias promises potential material in DC superposition application.