Enhancing Magnetic Properties of τ–Mn₅₃.₃Al₄₅C₁.₇ Through Sintering With Fe₅₈.₅Co₃₁.₅X₁₀ Alloys

In this study, powders of the
$\tau $
–Mn53.3Al45C1.7 hard magnetic phase were mixed and sintered with powders of the three soft magnetic phases, Fe58.5Co31.5X10 (X = Ti, Zr, and Ce), in a relation of 98/2 wt.%. The soft Fe58.5Co31.5X10 magnetic phases primarily exhibit an
$\alpha $
–FeCo crystalline phase. The Fe58.5 Co31.5 Zr10 and Fe58.5Co31.5Ce10 samples contain the FeCoZr and Ce2 (Fe,Co)17 phases, respectively. Mössbauer spectroscopy (MS) analysis of the soft magnetic phases was carried out using sextets and quadrupole splitting distributions (QSDs). In addition, a small hyperfine field distribution (HFD) was performed only for Fe58.5Co31.5Zr10. The majority sextet with a mean hyperfine field of 36.4 T was associated with the
$\alpha $
–FeCo phase, the most likely quadrupole splitting below 1.2 mm/s was associated with Fe
$^{+3}$
, and those more significant than this value were associated with Fe
$^{+2}$
. The hysteresis loops confirm the soft magnetic behavior, with saturation magnetization values of approximately 150 Am2kg-1. The
$\tau $
–Mn53.3Al45C1.7 phase reveals the presence of the
$\tau $
(84 wt.%) and
$\beta $
(16 wt.%) crystalline phases, along with magnetic properties such as magnetization at 1.8 T of 38.2 Am2kg-1, coercive field of 0.377 T, and maximum energy product of 3.6 kJm-3. The mixtures of both phases exhibit the soft magnetic phase
$\alpha $
–FeCo and
$\tau $
and
$\beta $
phases of the Mn-Al-C system. Among the three obtained mixed and sintered samples, the one mixed with Fe58.5Co31.5Zr10 demonstrates the best magnetic properties, with magnetization reaching 58.1 Am2kg-1, a coercive field of 0.361 T, and a maximum energy product of 7.4 kJm-3. All these magnetic properties surpass those of the
$\tau $
–Mn53.3Al45C1.7 phase, except for the coercive field.