Magnetic properties of 120-mm wide ribbons of high Bs and low core-loss NANOMET® alloy

Abstract

A 120-mm wide amorphous ribbon of a Fe-Co-Si-B-P-Cu NANOMET® alloy has been successfully produced by a single roll melt spinning technique. The optimally annealed samples exhibited low coercivity (Hc) of 5–7 A/m and high saturation magnetic flux density (Bs) of 1.83 T. The plots of Hc and Bs vs. annealing temperature (Ta) revealed basin-like and plateau-like characteristics, respectively, indicating the good annealing controllability for nanocrystallization and for obtaining soft-magnetic properties with high Bs. The excellent magnetic softness was attributed to the nanocrystalline structure composed of homogeneously dispersed α-Fe grains (with a size of 15–20 nm in diameter) emerged from the amorphous structure after optimum annealing. The nanocrystalline ribbons also exhibited low core-losses (W at 50 Hz) of 0.37 and 0.64 W/kg under maximum flux density of 1.5 T and 1.7 T, respectively. The magnetic properties were comparable with those of laboratory-scale small-width ribbons and confirmed to be independent on the ribbon width, indicating the good reproducibility of this NANOMET® alloy into mass-production-level precursors.

Outstanding efficiency in energy conversion for electric motors constructed by nanocrystalline soft magnetic alloy “NANOMET®” cores

“…As the same as previous report, 16 XRD profiles (not shown here) taken from the machined ribbon of the (a) as-quenched, (b) annealed states reveal that the profile of the as-quenched ribbon (a) consists of only a halo, and no Bragg peaks corresponding to crystalline phase and clear Bragg peak of a-Fe can be detected for the profile of the crystallized ribbon, indicating that the annealed ribbon is composed of a-Fe phase and residual amorphous structure.…”

“…As coincidence in the volume fraction of a-Fe grains, the value of B s for the present ribbon (1.83 T) is comparable to that of previously reported. 16 Unfortunately, the value of H c and W for the present ribbon is slightly higher than that of previous one. 16 These slight degradations are caused by the broadened grain size distribution.…”

“…16 Unfortunately, the value of H c and W for the present ribbon is slightly higher than that of previous one. 16 These slight degradations are caused by the broadened grain size distribution. Figure 3 shows the core-loss property as a function of induction maximum flux density (B m ) for the annealed ribbon.…”

“…The size distribution of the a-Fe grains by the present annealing seems to be slightly broadened as compared to the previous one. 16 In fact, the average grain size (d av ) and the standard deviation (σ) is evaluated to be 22 nm. This value is slightly bigger than those of previous result (10.9 nm), indicating that the relatively large grains contains in the present annealing ribbon.…”

Fe-Si-B-P-C-Cu nanocrystalline soft magnetic powders with high B s and low core loss

“…The nanocrystallization mechanism of "NANOMET " has been reported in by Takeuchi, et al 5 and Sharma, et al 6 Presently, most NANOMET samples are in the form of ribbon which are produced by a melt spinning method. 7 This technique is reliable to obtain good-quality amorphous precursors because of its high quenching rate. The properties of ribbon wound cores has been reported by Takenaka, et al Meanwhile, soft-magnetic powders are widely used for high frequency applications because of its low eddy-current loss.…”