EFFECT OF IRON CONCENTRATION ON CRYSTALLIZATION OF AN AMORPHOUS ALLOY OF CO-FE-B-NB SYSTEM

In the modern world, technical devices are being constantly improved, creation of which requires materials with the best functional properties. Amorphous and nanocrystalline iron- and cobalt-based alloys are some of such materials. They have proved to be good in the fields of radio- and microelectronics, due to the fact they have high magnetic characteristics. It is also known that these properties can be improved by the formation of a partially crystalline structure is such alloys. However, such a structure cannot always be formed using a standard method of isothermal annealing; therefore, alloying components are added to the alloy composition to slow down the crystallization process. Different content of added components also affects the sequence of phase transformations during crystallization. As most of the properties are structure-dependent, the formed structure also determines the material characteristics. Therefore, establishment of the dependence of the formed structure in amorphous alloys after heat treatment is an important task of condensed matter physics. The crystallization of the amorphous alloys of Co-Fe-B-Nb system was studied by X-ray diffraction. The samples were crystallized using isothermal annealing of the alloys with different content of components under the same conditions. The dependence of the formed structure on the content of an alloying component is determined. It is shown that the formed structure significantly depends on the concentration of iron. With the iron content of 10 at.% and 16 at.%, the structure consists of cubic cobalt nanocrystals and a solid solution of iron in cobalt. With a decrease in the concentration to 5 at.%, the crystallization mechanism changes: crystallization begins with the precipitation of Co₂₃B₆ boride crystals. The reasons for the effect of iron concentration in the alloy composition on crystallization are discussed.

amorphous alloys, nanocrystalline alloys, structure of nanocrystalline alloys, crystallization of amorphous alloys, X-ray diffraction analysis