On the usage of underwater plasma and magnetopulse processing of FeSiBNb amorphous alloy ribbons

Using the methods of scanning electron, optical and scanning probe microscopy, the surface structure of unannealed amorphous electrotechnical alloys — foils of the composition Fe₇₃(SiBNb)₂₇ and alloys of the same composition, but with the addition of 1% Cu, obtained by the method of ultra-fast cooling by spraying the melt on a rotating copper drum was studied. On the free surfaces of the foils not adjacent to the rotating drum, microformations, irregularities with “micropoints” with characteristic sizes of less than 0.5 microns were found, which during the operation of electrotechnical products can initiate the presence of electric field gradients on the surface of the foil. The effect of underwater plasma on the studied materials did not lead to a change in their magnetic characteristics. For Fe₇₃(SiBNb)₂₇ foil with the addition of 1% Cu, treated with 10 and 40 pulses of a weak magnetic field (10–100 kA/m) of low frequency (10–20 Hz), magnetic contrast was detected: in phase contrast mode after exposure to 40 pulses of a magnetic field, triangular figures associated with the appearance of closing prismatic domains, the width of the domain walls of which is approximately 1–2 μm, and after exposure to 10 pulses of a magnetic field — a magnetic contrast of a specific shape, which was observed over the entire studied area of the foil. Also, for Fe₇₃(SiBNb)₂₇ foil with the addition of 1% Cu, there was a weak dependence of the specific magnetization on the number of magnetic pulses: an increase in the number of pulses led to a slight decrease in the specific magnetization.