Resumen de Magnetic and Structural Characterization of Mechanically Alloyed Fe50co50 Samples
Germán Antonio Pérez Alcázar, Ligia E. Zamora, José Francisco Marco, Juan José Romero, Jesús María González, Francisco Javier Palomares
Samples of nominal composition Fe50Co50 were produced by mechanical alloying byusing a planetary ball mill and different milling times. The samples were studied via X-raydiffraction, Mössbauer spectroscopy, and X-ray photoelectron spectroscopy to characterize thephase distribution resulting from the milling process. The Mössbauer data indicated that Co startsdiffusing into Fe after 8 h of milling. Between t = 8h and t = 24 h the sample has a heterogeneouscomposition, presenting a bimodal hyperfine field distribution with maxima centred at 34.3 T and35.8 - 36.4 T, compatible with the presence of different Fe environments (richer in Co and richerin Fe, respectively). After 48 h of milling, the sample presents a more homogeneous compositionshowing an almost symmetric hyperfine magnetic field distribution centred at H=34.9 T,indicating that a disordered equiatomic FeCo solid solution has already been formed. The X-rayphotoelectron spectroscopy data indicate that the native oxide layer formed on the freshly milledsamples contains Co2+, Fe2+ and Fe3+ oxides. After complete removal of this native oxide layer byAr ion bombardment, X-ray photoelectron spectroscopy analysis yields the composition of thenominal equiatomic Fe50Co50 alloy.
