Tailoring phase transformation pathways to enhance magnetic performance in Ga-doped sintered Nd-Fe-B magnets
Source abstract
Abstract
The RE 6Fe 13 Ga phase (RE, Rare Earth) exhibits tremendous promise for achieving high-performance magnets. However, the challenge of controlling its formation and distribution hinders improvements in coercivity and squareness of Ga-doped magnets. In this study, we present a strategy to regulate the chemical composition of the RE-rich phase (0–9 at.% Cu, without Ga) and subsequently modify the phase transformation pathways of the RE 6Fe 13Ga phase in Ga-doped magnets by incorporating a Pr-rich Ga-Cu-containing aiding alloy. Remarkable magnetic performance was achieved, with values of B r=13.36 kGs, μ 0 H cj=20.82 kOe, (BH) max=43.75 MGOe, and μ 0 H k90/μ 0 H cj =0.99. Through quantitative analysis of chemical and structural properties and phase fractions at grain boundary (GB) triple junctions, we elucidate the phase transformation pathways in the magnets. The reaction between amorphous RE-Ga-rich phases and the matrix phases, along with partial consumption of the RE-rich phases with the Mn 2 O 3 -type structure (space group Ia 3 ¯ ), led to the formation of the RE 6Fe 13 Ga phase, accompanied by the presence of an amorphous Fe-rich transitional phase sharing a similar chemical composition. The gradual and partial involvement of the RE-rich phase improved the melt`s wettability and delayed the formation of the RE 6Fe 13Ga phase. Consequently, a uniform microstructure was achieved, establishing the conditions for high magnetic performance. Thin metallic GBs and thick RE-rich, amorphous Fe-rich, and RE 6Fe 13 Ga GBs were formed in the magnet. The former ensured squareness, while the sufficient coverage of the latter contributed to exceptional coercivity. The Pr-rich aiding alloy induces chemical heterogeneity, reinforcing the magnetic properties. This study advances our understanding of phase transformation pathways in Ga-doped magnets and introduces an effective approach for achieving high-performance magnets.
Source: expertdata · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Magnetic Properties of Alloys · Magnetic properties of thin films · Magnetic Properties and Applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
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