SKM 2023 – scientific programme
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MA: Fachverband Magnetismus
MA 28: Bulk Materials: Soft and Hard Permanent Magnets
MA 28.3: Talk
Wednesday, March 29, 2023, 10:00–10:15, POT 6
Ab initio thermodynamic modelling for Ce-based alternative hard magnetic materials — •Halil Ibrahim Sözen1, Tilmann Hickel2, and Thorsten Klüner1 — 1Institute of Chemistry, Carl-von-Ossietzky University of Oldenburg, D-26129 Oldenburg, Germany — 2BAM Federal Institute for Materials Research and Testing, 12489 Berlin, Germany
The utilization of the RE-lean ThMn12 materials system in combination with the abundant RE element Ce is a promising strategy for modern hard magnet applications. One of the main challenges for the Ce-based hard-magnetic materials is the formation of detrimental Laves phases next to the ThMn12-type compound CeFe11Ti. In this contribution, we present an ab initio-based approach to modify the stability of these phases in the Ce-Fe-Ti system by additions of 3d and 4d-elements. The results are used to provide two fundamental methodological insights. One of them is our recently developed modeling concept of partial decomposition, which considers the enrichment of the added solutes in phases that would at the considered temperature not be stable in a conventionally used full decomposition model. The second conclusion is the dominant impact of 0 K formation enthalpies on the solute-enhances phase stability compared to finite temperature entropy terms. Based on this, a screening approach is developed, considering the substitution of all 3d and 4d-elements. We show that substituted elements with more than a half-filled 3d-shell or with less than a half-filled 4d-shell mainly reduce the formation temperature of the 1:12 phase.