Industrialization of nanocrystalline Fe-Si-B-P-Cu alloys for high magnetic flux density cores

Nanocrystalline Fe-Si-B-P-Cu alloys exhibit high saturation magnetic flux density (B_s) and extremely low magnetic core loss (W), simultaneously. Low amorphous-forming ability of these alloys hinders their application potential in power transformers and motors. Here we report a solution to this problem. Minor addition of C is found to be effective in increasing the amorphous-forming ability of Fe-Si-B-P-Cu alloys. It allows fabrication of 120 mm wide ribbons (which was limited to less than 40 mm) without noticeable degradation in magnetic properties. The nanocrystalline (Fe_85.7Si_0.5B_9.5P_3.5Cu_0.8)₉₉C₁ ribbons exhibit low coercivity (H_c)~4.5 A/m, high B_s~1.83 T and low W~0.27 W/kg (@ 1.5 T and 50 Hz). Success in fabrication of long (60-100 m) and wide (~120 mm) ribbons, which are made up of low cost elements is promising for mass production of energy efficient high power transformers and motors