Decomposition behavior in the early-stage oxidation of Sm2Co17-type magnets. (15th July 2021)

• Record Type: Journal Article
• Authors: Zhang, Yong; Cao, Xun; Tan, Huiteng; Gill, Vincent; Lambourne, Alexis; Yan, Alex Qingyu; Huang, Yizhong
• Is Part Of: Scripta materialia. Number 200(2021)
• Publication Date: 2021-07-15
• Subjects: Permanent magnets -- Oxidation -- Decomposition -- TEM; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.113911
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Irredeemable magnetic loss caused by oxidation remains a critical concern for the application of Sm2 Co17 -type permanent magnets. Herein, oxygen induced decomposition in the early-stage oxidation of a Sm(Cobal Fe23.5 Cu4.9 Zr1.7 )7.5 magnet is studied using aberration-corrected TEM. Upon oxygen penetration along the 1:3R Z-plates, the 1:5H cell boundaries are decomposed into separate Sm and Co(Fe) lamellae with thicknesses of ~5 nm. Subsequently, the Fe-rich 2:17R cells are decomposed into similar metal lamellae. Besides the normal hexagonal stacking, the Sm lamellae also exhibit a twinned face-centered cubic (FCC) structure. The decomposed Co(Fe) lamellae and Cu particles are FCC-structured. The nano-twinned Cu particles are sparsely distributed. Interestingly, the closely-packed planes of these metal lamellae tend to align with the {0001}2:17R plane. The metal lamellae enriched with oxygen interstitials finally turn into nano-oxides by oxidation. This work offers in-depth insights into the initial oxidation behavior of alloys. Graphical abstract: Image, graphical abstract