HIGH-INDUCTION LOW-LOSS METALLIC GLASSES

Alloying effects of cobalt metal and the metalloids carbon, silicon, phosphorus, germanium, and aluminum in Fe80B20 glass are considered in terms of magnetization σ and in terms of Curie and crystallization temperatures TC and Tχ, respectively. Silicon additions are reported in detail and are shown to increase both T C and Tχ strongly while only weakly affecting σ (RT). The highest magnetization, Tc, and Tχ are found in the series Fe82B18-xSix. B-H loops and core loss are reported for Fe82B10Si8 glass. dc coercivities under 0.03 Oe, remanences over 12 kG and initial permeabilities of 8000 are obtainable in field-annealed toroids of this composition. Core loss under sine-flux conditions at 60 Hz is 0.24 W/kg at 16 kG compared with 1.3 W/kg for M-4 grade Si/Fe and well below that of Fe80B20 glass. The kinetics of crystallization of Fe82B10Si8 glass (E=2.7±0.1 eV, τ0≈3±1×10 -17 sec) show it to be slightly more resistant to crystallization than is Fe80B20 glass (E=2.67 eV, τ0=1. 75×10-17 sec).