Thermomagnetic Analysis of the Crystallization in Soft Magnetic Nanocrystalline Alloys

Abstract:

In this work, we investigated the dynamics of nanocrystallization from the amorphous state of the Fe_72.5Cu₁Nb₂Mo_1.5Si₁₄B₉ alloy together with magnetic phase transformations. The thermomagnetic analysis was performed with the simultaneous recording of the temperature inside the core by a thermocouple and the inductance of the winding wound over the core. It was found that the permeability of the core after the crystallization peak first increases rapidly, and then decreases and stabilizes at some level. Permeability growth begins at a temperature that coincides with the Curie point of the Fe₈₀Si₂₀ solid solution. A decrease in permeability was associated with stabilization of the structure of the amorphous and crystalline phases upon cooling. With decreasing temperature, the active redistribution of chemical elements is suppressed, and silicon atoms occupy a stable position in the crystal lattice of iron. Nanocrystalline cores have different Curie temperatures in the state after the peak of crystallization and 300 seconds after the peak. This indicates the continuation of the diffusion of silicon from the amorphous matrix into Fe-Si nanocrystals for some time after the crystallization peak.

• Periodical: Key Engineering Materials (Volume 846)
• Pages: 67-71
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.846.67
• Online since: June 2020
• Authors: Vladimir S. Tsepelev*, Yuri N. Starodubtsev, Kai Ming Wu, Nadezhda P. Tsepeleva
• Keywords: Crystallization, Curie Point, Nanocrystalline Alloy, Soft Magnetic Alloy

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