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The effect of 10 at % Mn introduced into the classic FINEMET (Fe73.5Cu1Nb3Si13.5B9) at the expense of Fe on the magnetic properties, magnetic anisotropy, and structure, which are formed after nanocrystallizing annealing at 520°C for 10 min to 4 h in the presence of tensile stresses σ = 200 MPa and in the absence of them, is studied. It is shown that, for the Fe63.5Mn10Cu1Nb3Si13.5B9 alloy, like for the classic FINEMET, the annealing in the presence of tensile stresses results in inducing the transverse magnetic anisotropy; however, the constant of induced magnetic anisotropy decreases by 4 times. The coercive force of the Mn-containing alloy increases as the time of annealing both in the presence of tensile stresses and without them increases, whereas the coercive force of FINEMET is almost unchanged. It is shown that the Mn-containing alloy subjected to 10-min treatments already is characterized by the presence of the borides along with the α-Fe(Si, Mn) solid solution and Fe3Si phase. This leads to changing the ratio of volume fractions of structure constituents with the negative and positive magnetostriction, which is likely to cause the decrease in the induced magnetic anisotropy constant of the Mn-containing alloy. The average grain size in the Mn-containing alloy is shown to increase as the time of treatments increases; this fact, along with the formation of borides, leads to the increase in the coercive force. [ABSTRACT FROM AUTHOR]

In the alloy Fe63.5Ni10Cu1Nb3Si13.5B9, which is conventional FINEMET with Fe replaced by 10 at % Ni, the effects of the temperature and time of nanocrystallizing annealing in the presence of tensile stresses (stress annealing, SA) on the magnetic properties, magnetic anisotropy, and structure are considered. In the entire studied SA temperature range (480–550°С), induced magnetic anisotropy (IMA) of the easy-plane type occurs in the studied alloy. The tensile stresses upon SA were 200 MPa. In the course of SA at the minimum temperature, anisotropy with the minimum IMA constant (200 J/m3) is induced. The maximum SA duration, i.e., 4 h, is required. At SA temperatures of 540–550°С, 10 min is sufficient to induce IMA with the maximum constant ~2000 J/m3. It is shown that the structural state (phase composition) is correlated with the magnetic properties and IMA. Thus, the increase in the coercivity with an increase in the SA duration at 540–550°С (as well as at 520°С) is due to the development of the tetragonal phase in the alloy. The α‑(Fe,Ni)Si solid solution and Fe3Si phases form upon treatment for 10 min. The decrease in the IMA constant with an increase in the SA time at 540–550°С from 10 min to 1 h is most likely due to the change in the volume fractions of the structural components of the alloy with negative and positive magnetostriction. [ABSTRACT FROM AUTHOR]

The effect of 10 at % Ni, which was introduced into the classic Finemet Fe73.5Cu1Nb3Si13.5B9 at the expense of the Fe content, on the magnetic properties of the composition has been considered. The alloy was subjected to nanocrystallizing annealing in the presence of tensile stresses and in their absence. It is shown that, similarly to the Ni-free alloy, in the Fe63.5Ni10Cu1Nb3Si13.5B9 alloy subjected to thermomechanical treatment, the magnetic anisotropy with the easy magnetization direction across the ribbon axis (transverse induced magnetic anisotropy) is induced. It was found that the 10 at % Ni addition almost does not affect the value of magnetic anisotropy constant induced under thermomechanical treatment and decelerates the process of magnetic anisotropy inducing at σ ≤ 200 MPa. The Ni-containing alloy subjected to nanocrystallizing annealing (at 520°C) in the presence of tensile stresses and in their absence demonstrates the more than 200-fold increase in the coercive force as the annealing time increases from 1 to 4 h, whereas the coercive force of the Ni-free alloy is almost unchanged. This is likely to be related to the appearance of new structural components in the Ni-alloyed composition upon annealing. [ABSTRACT FROM AUTHOR]