Structure and magnetic properties of NdFeB powder surrounded with layer of rare-earth fluorides

Autor:	Matahiro Komuro, Yuichi Satsu
Rok vydání:	2008
Předmět:	Materials science Annealing (metallurgy) Hexagonal crystal system Metallurgy Rare earth General Physics and Astronomy Lanthanum compounds Coercivity chemistry.chemical_compound Neodymium magnet Chemical engineering chemistry Magnetic nanoparticles Fluoride
Zdroj:	Journal of Applied Physics. 103:07E142
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.2829998
Popis:	The effect of a layer of rare-earth fluorides on the structure and magnetic properties of NdFeB powders was studied. Rare-earth fluorides such as REFx (RE: rare-earth element, x=2 or 3) were grown using fluoride liquid solutions in order to cover the surface of the NdFeB powders. For NdFx-coated NdFeB powder, NdF3 with a hexagonal structure was grown below 400°C. A structure change from NdF3 to cubic NdF2 was observed after annealing at the temperature of 400°C or more. Coercivity (iHc) for 3vol% NdFx-coated NdFeB powder decreased to 14.0 from 15.0kOe for noncoated NdFeB powder after annealing at 800°C. The rare-earth fluoride layers of LaFx-, TbFx-, and DyFx-coated NdFeB powders showed a iHc of 16.8, 16.6, and 16.4kOe, respectively, all of which were higher than that for noncoated NdFeB powder, indicating a diffusion of rare-earth atoms in the fluoride layer.
Databáze:	OpenAIRE
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