The dependence of coercivity and corrosion resistance on grain size in Nd-Fe-B-type sintered permanent magnets
Year: 1991
Type: article
Abstract: The microstructure, effect of grain size on the coercivity and corrosion behaviour of Nd 14 DyFe 69.5 Co 5 AlCr 2 B 7.5 sintered magnets have been investigated. Besides the hard magnetic boride phase (Nd,Dy) 2 (Fe,Co,Al,Cr) 14 B, a boron-rich phase (Nd,Dy) 1+ in (Fe,Co,Cr) 4 B 4 and non-magnetic Nd-Co phase (probably Nd 3 Co) along grain boundaries were detected in sintered magnets. The coercivity and domain structures of the magnets with various mean grain size were analysed. It is shown that the coercivity decreases with increasing grain size and depends on the homogeneity of the distribution of the non-magnetic Nd-rich phase along grain boundaries. The corrosion resistance of the investigated magnets is also improved by the formation of a Nd-Co grain boundary phase, probably Nd 3 Co and, generally, it increases with increasing mean grain size.
Institution: Częstochowa University of Technology
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1989146407