New alnico magnets fabricated from pre-alloyed gas-atomized powder through diverse consolidation techniques

Journal Article · Mon May 25 00:00:00 EDT 2015 · IEEE Transactions on Magnetics

DOI:https://doi.org/10.1109/TMAG.2015.2437355· OSTI ID:1234461

Tang, W. ^[1]; Zhou, L. ^[1]; Kassen, A. G. ^[1]; Palasyuk, A. ^[1]; White, E. M. ^[1]; Dennis, K. W. ^[1]; Kramer, M. J. ^[1]; McCallum, R. W. ^[1]; Anderson, I. E. ^[1]

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1. Iowa State Univ., Ames, IA (United States)

Fine Alnico 8 spherical powder produced by gas atomization was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and magnetic properties were analyzed and compared. The HP, HIP, and CMS magnets exhibited different features in microstructures and magnetic properties. Magnetically annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (H_cj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. As a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1234461
• Report Number(s): IS-J-8871
• Journal Information: IEEE Transactions on Magnetics, Vol. 51, Issue 11; ISSN 0018-9464
• Publisher: Institute of Electrical and Electronics Engineers. Magnetics Group
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
alnico permanent magnets
gas atomization powder
hot pressing
magnetic properties
sintering