Nanocomposites and nanomaterials

Nanocrystallization and magnetic properties 
of amorphous cobalt-based alloys
Nykyruy Y.S.1, Mudry S.I.1, KulykY.O.1, Prunitsa V. 1, Borysiuk A.K.2
1 Metal Physics Department, Ivan Franko National University of Lviv, Kyrylo and Mephodiy, 8, 79005 Lviv, Ukraine
E-mail: yuliya.nykyruy@lnu.edu.ua
2 Department of Applied Physics and Nanomaterial Science, Lviv Polytechnic National University, Ustijanovicha 5, 79013 Lviv, Ukraine

Co-based amorphous metal alloys (AMA) for a long time are under research due to their unique properties [1, 2]. These materials after optimum heat-treatment exhibited superior soft magnetic properties and have found applications in sensor elements, cores, choke coils, etc. Present research is focused on nanocrystallization behaviour and magnetic properties of the amorphous alloys with compositions Co73Fe1Mo1Mn3Si13B9, Co70Fe3Mo1.5Mn3.5Si11B11, and Co57Ni10Fe5Si11B17. Alloys were manufactured in the form of the ribbons by rapid cooling from the melt using the melt-spinning technique. The ribbon thickness and width were about 25 µm and 1 cm respectively. 
The as-obtained ribbons were investigated by the DTA-method using synchronous thermal analyzer Linseis STA PT 1600 under dynamic argon atmosphere (~6 liters per hour). Heating was performed at the rate of 10 K/min from 293 K up to 973 K. The temperatures of the onset of the nanocrystallization and further structure transformations were defined.
The ribbons structure was investigated using the back-scattered X-ray diffraction (XRD) method. Magnetic measurements were performed using a vibrating magnetometer. Re-magnetization curves of the studied samples were recorded in a magnetic field from –300 kA/m to +300 kA/m. The specific saturation magnetization (σs) and its temperature dependence were measured in the magnetic field of 800 kA/m.

1.	Mudry, S.I., Nykyruy, Y.S. Laser induced structure transformation in Co70Fe3Mn3.5Mo1.5B11Si11 amorphous alloy // Mater Sci-Pol. – 2014–32.–P. 28–33. https://doi.org/10.2478/s13536-013-0152-2
2.	Mudry, S.I., Nykyruy, Y.S. Structural changes and mechanical properties of amorphous metallic ribbons Fe–(Ni, Co, Mn)–Mo–Si–B irradiated by powerful nanosecond laser pulses // Chem. Met. Alloys.-2011.- 4.-P. 85-88