Rev. Phys. Appl. (Paris) 25, 1205-1211 (1990)
DOI: 10.1051/rphysap:0199000250120120500
Studies on sintered permanent magnets RE-Fe-M-Co-B (RE = Nd, Pr, Dy, Tb; M = Si, Al, Cr)
H. Bala1, S. Szymura2, Yu. M. Rabinovich3, V.V. Sergeev3, G. Pawlowska1 et D.V. Pokrowskii31 Institute of Chemistry, Technical University, al. Zawadzkiego 19, PL-42-200 Czestochowa, Poland
2 Institute of Physics, Technical University, al. Zawadzkiego 19, PL-42-200 Czestochowa, Poland
3 Department of Magnetic Materials, VNEM, Prospect Kalinina 19, Moscow, U.S.S.R.
Abstract
The microstructure, magnetic properties and corrosion behaviour of RE 16Fe7(1-x)M(x)Co5B8 (RE = Nd, Pr, Dy, Tb ; M = Si, Al, Cr) sintered magnets have been examined. It was established that the presence of Re-(Co, Fe, M) compound along the grain boundaries of these alloys was responsible for inhibition of the corrosion in acid solution and in atmospheric environment. The best magnetic properties obtained in these studies are Br = 1.26 T and MHc = 1 730 kA/m for the Nd14DyTbFe70SiCo5B8 alloy.
Résumé
La microstructure, les propriétés magnétiques et le comportement à la corrosion des aimants frittés RE16Fe7(1-x)M(x)Co5B8 ont été étudiés. (RE désigne Nd, Pr, Dy, Tb et M désigne Si, Al, Cr). Il a été montré que la présence de composés RE-(Fe, Co, M) aux joints de grains est responsable de l'inhibition des corrosions acide et atmosphérique. Les propriétés magnétiques optimales déduites de cette étude sont Br = 1,26 T, MH c = 1730 kA/m pour la composition Nd14DyTbFe70SiCo5B8.
7560G - High coercivity magnetic materials.
6480G - Microstructure.
7550B - Ferromagnetism of Fe and its alloys.
8160B - Surface treatment and degradation of metals and alloys.
6170N - Grain and twin boundaries.
3110C - Ferromagnetic materials.
Key words
aluminium alloys -- boron alloys -- chromium alloys -- cobalt alloys -- crystal microstructure -- ferromagnetic properties of substances -- iron alloys -- permanent magnets -- rare earth alloys -- silicon alloys -- sintered permanent magnets -- RE Fe M Co B -- microstructure -- magnetic properties -- corrosion -- grain boundaries -- acid solution -- atmospheric environment -- Nd Fe Co B -- Pr Fe Co B -- Dy Fe Co B -- Tb Fe Co B