Measurements on permanent magnets made from misch metal-cobalt alloy powders

Powders of a misch metal-cobalt alloy of type (MM)Co
5
were prepared and consolidated in various ways to study the effects of particle size, plastic deformation during milling, and pressure applied during compacting on the permanent magnet properties. Vibration grinding yields particles with high coercive force (
M
H_{c} = 4180
Oe) but which align very poorly in a field. Mortar-ground powders have high magnetic anisotropy combined with much lower, but strongly particle-size dependent H
c
. Ballmilling, a method suitable for production in quantity, constitutes a satisfactory compromise. Pressing ballmilled powder in a field with 3400 kg/cm
²
pressure and no binder gave optimum results. A magnet having
M
H_{c} = 2010
Oe,
B
H_{c} = 1620
Oe,
B_{r} = 4060
G, and
(BH)_{\max} = 2.34
MG.Oe was obtained. Details of the static and recoil behavior for this magnet are reported.