Role of Surface Iron Oxides in Coercivity Deterioration of Sm2Fe17N3 Magnet Associated with Low Temperature Sintering
- 1 March 2019
- journal article
- research article
- Published by Japan Institute of Metals in MATERIALS TRANSACTIONS
- Vol. 60 (3), 479-483
- https://doi.org/10.2320/matertrans.m2018358
Abstract
Sm2Fe17N3 powders were analyzed by X-ray photoelectron spectroscopy to elucidate the role of surface Fe oxides in the significant deterioration of coercivity observed when Sm2Fe17N3 is sintered at relatively low temperatures. It was demonstrated that the Fe oxides on the powder surface completely disappear after heat treatment at 500°C in Ar. This suggests that the chemical reaction which causes the coercivity deterioration involves consumption of the Fe oxides. A reaction model that postulates a redox reaction between the Fe oxides and Sm2Fe17N3 to produce soft-magnetic α-Fe consistently explains both the coercivity drop and the consumption of the Fe oxides. The conventional model of simple Sm2Fe17N3 decomposition, on the other hand, cannot rationally explain the disappearance of the Fe oxides. It is therefore reasonable to consider the redox reaction to be the primary mechanism of coercivity deterioration, in which the Fe oxides play a role as one of the major reactants.Keywords
This publication has 17 references indexed in Scilit:
- The state of the art of wind energy conversion systems and technologies: A reviewEnergy Conversion and Management, 2014
- Electrical Motor Drivelines in Commercial All-Electric Vehicles: A ReviewIEEE Transactions on Vehicular Technology, 2011
- Study of thermal decomposition mechanism of the Fe/sub 17/Sm/sub 2/N/sub 3/ phaseIEEE Transactions on Magnetics, 1996
- Magnetic properties of sintered Sm2Fe17Ny magnetsJournal of Applied Physics, 1993
- Effect of nitrogen content on magnetic properties of Sm/sub 2/Fe/sub 17/N/sub x/ (0<x<6)IEEE Transactions on Magnetics, 1992
- B materials: Intrinsic properties and technological aspectsReviews of Modern Physics, 1991
- Magnetic properties of R2Fe17N2.7 compoundsJournal of the Less Common Metals, 1991
- Metal bonded Sm2Fe17N3−δ magnetsJournal of Applied Physics, 1991
- Magnetic properties of a new family of ternary rare-earth iron nitrides R2Fe17N3−δ (invited)Journal of Applied Physics, 1991
- Improved magnetic properties by treatment of iron-based rare earth intermetallic compounds in anmoniaJournal of Magnetism and Magnetic Materials, 1990