Bonded ferrite-based exchange-coupled nanocomposite magnet produced by Warm compaction

authors	Mohseni, F; Pullar, RC; Vieira, JM; Amaral, JS
nationality	International
journal	JOURNAL OF PHYSICS D-APPLIED PHYSICS
author keywords	hexagonal ferrite; magnetite Fe3O4; magnetic exchange coupling; nanocomposite hard magnets; exchange-spring magnets; bonded magnets
keywords	STRONTIUM FERRITE; PERMANENT-MAGNET; SOFT
abstract	Many modern technologies require permanent magnets with combinations of properties that cannot be met by conventional metallic or ceramic magnets. Ferrite/polymer composite magnets are a type of rare-earth free magnet with a wide range of magnetic and material property combinations. The uncertainty surrounding the supply and pricing of rare-earth elements, along with environmental issues of using these elements, have motivated many researchers to develop high-performance ferrite-based magnets via an exchange spring method. The present study explores magnetite coated M-type ferrite nanocomposites synthesised via a hydrothermal and coprecipitation method, and investigates the mechanical and magnetic properties of warm compressed high-performance exchange-coupled nanocomposites in an epoxy matrix. We show how the powder-to-resin ratio and preparation conditions lead to optimised mechanical properties, and enhancement in the maximum energy product of the composite magnet by up to 120% compared to a commercial SrM bonded plasto-ferrite magnet. These high performance composite magnets can lower the final cost of ferrite based bonded magnets without reducing the permanent magnetic properties or can be used in applications that a ferrite magnet has inadequate performances.
publisher	IOP PUBLISHING LTD
issn	0022-3727
isbn	1361-6463
year published	2020
volume	53
issue	49
digital object identifier (doi)	10.1088/1361-6463/abb0bd
web of science category	Physics, Applied
subject category	Physics
unique article identifier	WOS:000573477700001