Structural characterization of two-phase soft magnetic alloys obtained by twin-roller melt-spinning.

J. M. SILVEYRA; G. POZO LÓPEZ; L.M. FABIETTI; A.M. CONDÓ; B. ARCONDO

Workshop; X-LAW3M, Latin American Workshop on Magnetism, Magnetic Materials and their Applications; 2013

Two-phase Fe 73,5- Si 13,5- B 9- Nb 3- Cu 1 ultra-soft magnetic alloys were produced in the form of ribbons by the twin-roller melt spinning technique. Tangential wheel speeds between 15 and 20 m/s were applied to impose different quenching rates from the melt, in order to further investigate the resulting microstructures and their magnetic properties. Two relevant parameters controlling the magnetic behavior of these nanocrystalline alloys are the volume fractions of amorphous and crystalline phases and the actual chemical composition of these phases. Since the chemical analysis, e.g. Electron Microprobe Analysis, is not quite precise at the nanoscale, other techniques were applied to determine the chemical composition of the two phases in the partially crystallized samples. The structural and chemical study of the melt spun alloys was addressed by Transmission Mössbauer Spectroscopy and complemented with results obtained by Transmission Electron Microscopy and X-ray Diffraction. Additionally, magnetoimpedance measurements were performed to investigate the magnetic anisotropies and the magnetization dynamics in the samples, correlating them with the nanostructures resulting from the fabrication processes.