Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

Abstract

<jats:p>Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.</jats:p>

Correlation between Microstructure and Magnetism in Ball-Milled SmCo5/α-Fe (5%wt. α-Fe) Nanocomposite Magnets

“…As it has been evidenced so far for other ball-milled intermetallics [ 16 , 17 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 58 , 59 ], the d cryst is significantly reduced in the first stages of mechanical synthesis (here, it is noted just after 0.5 h) and further grinding is reflected only in its slight variation. As it was evidenced by, e.g., Rama Rao et al [ 53 ], the crystallite size for the same quantity of Fe is significantly reduced after 20 h of milling, starting from about 30 (4 h) to 5 nm (20 h).…”

“…In addition, the occurrence of the mechanically activated diffusion process leading to Fe/Co intermixing was evidenced as diffusion of Fe atoms in the SmCo 5 phase and Co atoms in the α-Fe phase. Such phenomena were noted for 10-30 wt.% of α-Fe-based materials [13,40,[47][48][49][51][52][53][54][55][56][57][58]. The interdiffusion process might be controlled by the annealing procedure, which is also reflected in the increase in grain size [13].…”

“…So far, SmCo 5 -based nanocomposites have been synthesized in an argon atmosphere or by the use of the wet SA-HEBM procedure, usually applied for up to 10 h, and also by magnetic field-assisted HEBM [ 13 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ]. The comparison of properties achieved for magnetic field-milled SmCo 5 /α-Fe nanocomposite powders with 10 wt.% of α-Fe made by Saravanam et al [ 13 , 46 ] with and without surfactants emphasizes the influential role of wet milling [ 46 ].…”

The Effect of Variation in the Number of Pole and Air Gap on Torque Density on Radial Magnetic Spur Gear with Magnetic Block

“…It is known that the greater the residual induction (Br) and coercivity (Hc), the better the properties of the object are to maintain the external magnetic field. However, until now, there are only four types of magnets that are commonly used as permanent magnet materials, namely AlNiCo [11], Feritte [12], SmCo5 [13], and the most recently discovered, NdFeB [14]. The properties of these materials is shown in Table 1.…”

Multifunctional Magnetic Nanocomposites: Innovative Processing and Applications

“…Maximum energy products comparable with specific values of present performing permanent magnets were obtained on samples annealed at 500 °C, demonstrating a new route to obtain rare-earth-free nanocomposite magnets with interfacial exchange-coupled hard–soft magnetic nanophases. Further on, exchange-coupled nanocomposites consisting of SmCo 5 + 10 wt% Fe were reported by Arnab Chakraborthy et al in [ 11 ]. It should be noted that the SmCo 5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation.…”