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The coercive force and residual magnetization have been examined as functions of angle for textured powder specimens of Sm0.5Pr0.5Co5 of particle size 1–50Μ made by mechanical crushing; similar results are presented for sintered magnets.

The new process for the production of pure iron powder with an iron content of the order of 99.9% is simple and can be mechanized. The resulting powder has excellent processing characteristics and in particular, as demonstrated by tests conducted at various organizations, can be successfully utilized for the production of sintered magnets, magnetic cores, high-density constructional parts, etc. In addition, the powder is also likely to find application as a charge material in the manufacture of steel powders and in the production of alloys with special electrical, magnetic, and physical properties.

In Co 5 Sm, the coercive force of aggregates of powders or sintered magnets is much greater at 77 K than at room temperature. In single particles, the field at which an individual magnetization jump occurs increases rapidly and monotonically with decreasing T. On the other hand, the K reported for Co 5 Sm is the same at 77 K and room T, with a broad maximum between. It thus appears that the reversal process is not controlled by the properties of bulk Co 5 Sm. The observed T dependence must be ascribable to the imperfections that govern the magnetization reversal process.

Hysteresis loops of small but still multi‐grain samples taken from sintered Co5Sm magnets show a wide range of behavior, samples from the same magnet bracketing the bulk properties. Magnetization discontinuties often appear and are associated with large grains. These jumps show a quantized dependence of jump field on magnetizing field and often a good 1/cosϑ dependence, exactly as in particles prepared from cast material. A sample consisting of only one grain gave a completely rectangular loop. Measurements on sintered magnets indicate that large grains tend to reverse in small fields, detracting from the overall properties.

An initial investigation of the liquid phase sintering of Sm2Co17 using a 60 wt% Sm ‐ 40 wt% Co sintering aid has been conducted. The total samarium content was varied from 25.3 wt% to 34.5 wt% through sintering aid additions, with the resulting phases present in the sintered magnets being uncertain. The sintering temperature was varied from 1110°C to 1140°C for a sintering time of 30 minutes. With the exception of the saturation induction, Bs, which decreased approximately 20%, the magnetic properties increased with increasing samarium content. This was particularly true of the intrinsic coercive force, Hci, which increased as much as eighteenfold, while the coercive force, Hc, and the energy product, (BH)max, each increased approximately sixfold. The residual induction, Br, also increased, but only by approximately 20%. The best initial results yielded a magnet with the following properties: Br = 6.0 kG, Hc = 3.8 kOe, Hci = 9.0 kOe and (BH)max = 6.4 MGOe.

Cu- and Fe-modified CeCo 5 magnets were prepared by a sintering technique, and their magnetic properties were studied. They exhibited an extremely square hysteresis loop and 12 MG.Oe maximum energy product.