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Title: High temperature oxidation and its induced coercivity loss of a 2:17 type SmCo-based magnet

Oxidation has been explained as one possibility for unacceptable and irreversible coercivity loss of 2:17 type SmCo-based magnets at high temperatures over 550 °C, but the question for how oxidation affects coercivity in the magnet has not been fundamentally answered. In this work, oxidation and its induced degradation of the magnetic phases of a Sm(Co{sub bal}Fe{sub 0.22}Cu{sub 0.08}Zr{sub 0.02}){sub 7.5} magnet in air at 600 °C have been investigated by using transmission electron microscopy and correlated with the demagnetization curves measured. It shows that the coercivity loss, which is significantly increased with oxidation time, is small and independent of time in the magnet unaffected by oxidation. The reason lies in that the 2:17 cell and 1:5 cell boundary, although they have been completely disintegrated in the oxidized part by external oxidation of Co, Fe, and Cu and internal oxidation of Sm, remains in the unoxidized part except that 1:5 boundary close to the oxidized part is decreased in thickness and Cu content.
Authors:
 [1] ;  [2] ; ; ;  [1] ; ;  [3]
  1. Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)
  2. (China)
  3. Division of Functional Materials, Central Iron and Steel Research Institute, Beijing 100081 (China)
Publication Date:
OSTI Identifier:
22413201
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COBALT; COERCIVE FORCE; COPPER; DEMAGNETIZATION; INTERMETALLIC COMPOUNDS; IRON; MAGNETIC MATERIALS; MAGNETS; OXIDATION; SAMARIUM; TRANSMISSION ELECTRON MICROSCOPY; ZIRCONIUM