A structural investigation of SmCo₅/Fe nanostructured alloys obtained by high-energy ball milling and subsequent annealing

Abstract

SmCo 5 /Fe nanostructured alloys with 20 wt% Fe, obtained by high energy ball milling of SmCo 5 and Fe powders, were investigated by 57 Fe Mössbauer spectrometry, X-ray diffraction and tomographic atom probe. The Mössbauer analysis reveals that during the first stages of milling, an interdiffusion of Co and Fe occurs, leading both to the formation of α-Fe(Co) regions in α-Fe and to the introduction of Fe in SmCo 5 regions. Annealing at temperatures up to 650°C for 0.5h promotes interdiffusion further leading to the formation of an unique α-Fe(Co) phase and a Fe-richer Sm(Co,Fe) 5 phase. The Co/Fe interdiffusion is confirmed by tomographic atom probe analysis. The data are discussed and compared to the results of previous magnetic measurements.

Advances in nanostructured permanent magnets research

“…A graded composition across the interface between the hard and soft phases was confirmed by both EDS and PEELS line scan profiles as seen in figure 2 [68]. Breton et al [69] showed their similar results in a recent report on ball milled and annealed SmCo 5 /Fe alloy characterized using different analytical techniques.…”

Exchange-Coupling Behavior in SrFe12O19/La0.7Sr0.3MnO3 Nanocomposites

“…Hence, it is important to obtain samples with no impurities and strong exchange-coupling interactions. The majority of reported methods for the synthesis of exchange-coupled composites are two-step methods: first the individual synthesis of hard and soft magnetic phase materials and later the exchange-coupling either via ball milling [16], chemical treatment [17], electroplating [18] or heat treatment [19]. To realize the exchange-coupling, it is required to achieve a high level of homogeneous mixing of the hard and soft phases, which is possible if the growth of both of these phases takes place together from a single reaction mixture.…”

The influence of short time heat treatment on the structural and magnetic behaviour of Nd2Fe14B/α-Fe nanocomposite obtained by mechanical milling

“…Same type of studies on SmCo 5 /␣-Fe exchange spring nanocomposite evidenced also two sextets for Fe. In this case, as result of Co and Fe interdiffusion, the two sextets were attributed to ␣-Fe(Co) phase and a Fe-richer Sm(Co, Fe) 5 phase [27].…”