Regensburg 2025 – scientific programme

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MA: Fachverband Magnetismus

MA 31: Poster II

MA 31.3: Poster

Wednesday, March 19, 2025, 17:00–19:30, P1

Structural and magnetic properties of Bi-bonded Mn-Al-C-Ti magnets — •Semih Ener, Fernando Maccari, Konstantin P. Skokov, and Oliver Gutfleisch — Functional Materials, Technical University of Darmstadt, Peter-Grünberg-Str. 16, D-64287, Darmstadt, Germany

In this study, the influence of Ti doping on the phase formation and magnetic properties of Mn-Al-C-Ti alloys is investigated. The alloys were synthesized by melt spinning followed by thermal treatment to obtain the ferromagnetic τ-phase, which was determined to be 20 min at 550 ^∘C for all Ti compositions.

However, the Ti-doped samples exhibited β-phase formation due to partial phase decomposition, with TiC precipitates observed at higher Ti concentrations. Doping resulted in an increase in the Curie temperature from 557 K in the undoped sample to 600 K in the Ti-doped samples.

In order to increase the coercivity, a combination of ball milling and hot compaction was used along with the introduction of Bi as a metallic binder. This resulted in an increase in coercivity, from 0.18 T to 0.33 T, as the addition of Bi facilitated the formation of a grain boundary phase, which aided in densification. This work demonstrates how compositional and processing modifications can be used to improve the magnetic properties of Mn-Al based magnets.

[1] J.S. Trujillo Hernández, F. Maccari, J.A. Tabares, K.P. Skokov, G.A. Pérez Alcázar, O. Gutfleisch and S. Ener, J. Magn. Magn. Mater. 610 (2024) 172573.

Keywords: MnAlC alloys; Rare earth free permanent magnet; Hot compaciton; metal bonding