The Influence of Composition and Field Annealing on Magnetic Properties of FeCo-based Amorphous and Nanocrystalline Alloys
CARNEGIE-MELLON UNIV PITTSBURGH PA
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We report the influence of composition and very high transverse field annealing on the magnetic properties and structure of four FeCo-based amorphous and nanocrystalline alloys. The compositions Fe50Co5089Zr7B4 and Fe65Co3589Zr7B4 were investigated changing the FeCo ratio from 5050 to 6535. Fe50Co5085Zr2Nb4B8.5 was chosen to investigate Nb substitution for Zr in an FeCo-based alloy. This substitution is shown to increase the magnetostrictive constant, lambdaS, of the nanocrystalline alloy from 36x10exp -6 to 54x10exp-6. The composition Fe65Co3584Cr5Zr7B4 was studied to investigate the influence of Cr on intergranular coupling across the amorphous matrix. Samples of each composition were annealed in the amorphous state at 300 C and in the nanocrystalline state at 600 C. Field annealing was performed in 17T transverse field in an inert atmosphere. Frequency-dependent magnetic properties were measured with an automatic recording hysteresisgraph. Static magnetic properties were measured with a vibrating sample magnetometer. The mass-specific power loss of the alloys decreased with field annealing in both the nanocrystalline and amorphous states for some frequency and induction combinations. Furthermore, the hysteresis loops are sheared after field annealing, indicating a transverse magnetic anisotropy. The nanocrystalline Fe50Co5085Zr2Nb4B8.5 composition has a lower relative permeability than the other compositions.
- Properties of Metals and Alloys
- Miscellaneous Materials