Mössbauer Study of Mechanosynthesized and Thermally Treated Co-Fe-Ni Alloys

Mechanical alloying was used to prepare $Co_{40}Fe_{60}$, $Co_{60}Fe_{35}Ni_{5}$, $Co_{40}Fe_{45}Ni_{15}$, and $Co_{40}Fe_{35}Ni_{25}$ alloys from the elemental powders. As X-ray diffraction studies proved the final products of milling were the solid solutions with bcc or fcc lattice and the average grain size between 20 and 50 nm. After heating of the alloys up to 993 K, the mixtures of two solid solutions with bcc and fcc lattices were formed in the case of Co-Fe-Ni alloys. Thermal treatment did not influence the type of the lattice of $Co_{40}Fe_{60}$ alloy. The Mössbauer spectroscopy revealed hyperfine magnetic field distribution ranged from 33 to 38 T for $Co_{40}Fe_{60}$ alloy and from 30 to 37 T for Co-Fe-Ni alloys. In the case of two-phase alloys, distributions were decomposed into two simple Gaussian functions using the numerical fitting. Magnetic measurements allowed to determine the effective magnetic moments and the Curie temperatures of the obtained alloys