Cobalt-Mischmetal-Samarium Permanent Magnet Alloys: Process and Properties

Abstract

Several authors have reported successful fabrication of high‐energy product (15–20 MGOe) Co₅R‐type cobalt‐samarium permanent magnets. In earlier papers we have described preparation of such magnets by a liquid‐phase sintering process sequence which includes powder preparation, magnetic alignment, pressing, sintering, and magnetizing. We have also described preparation of ternary compositions, primarily Co–Sm–Pr, by this process. In an effort to utilize more abundant rare‐earth metals, the cobalt‐mischmetal‐samarium system has been studied. Initial results indicate that a substantial fraction of the samarium may be replaced with mischmetal and still obtain high magnetic properties (BH_max 20 MGOe). Complete documentation of magnetic properties, i.e., saturation, remanence, coercive force, intrinsic coercive force, (BH)_max, and temperature coefficients are presented along with a discussion of the fabrication techniques utilized for preparation of the samples.