Abstract: The brittle nature and magnetic properties of the rare earth cobalt magnet are improved by the simultaneous addition of Cu and V. Cu and V are included in amounts of from 0.5 to 6% by weight and from 7 to 19% by weight, respectively. The simultaneous addition enables the rear earth cobalt magnet to be cast in the form of an article. In addition, the simultaneous addition not only improves the mechanical properties of the sintered article, in which form the conventional magnet was available, but also the magnetic properties, such that, for example, the coercive force is increased when the molar ratio of cobalt with respect to rear earth elements is great.

Abstract: Semi-hard magnetic materials exhibiting an excellent square hysteresis loop are prepared by the following steps. An alloy material consisting essentially, by weight, of 73-93% Co, 1-5%Nb and the balance Fe is subjected to process annealing at not lower than 900.degree. C and cold working at a reduction of area of not less than 75% and then is subjected to any combination treatment involving one or more stress relief annealings at a temperature in the range 500.degree.-700.degree. C for a short period of time such that no intermetallic compound precipitates in said alloy followed by cooling to the ambient temperature, and one or more ageing treatments of said cooled material at a temperature in the range 600.degree.-900.degree. C for a considerably longer time such that an intermetallic compound does precipitate in said alloy.

Abstract: A semi-hard magnetic alloy is disclosed consisting essentially of 15 to 30% of Ni, 35 to 52% of Fe, 1 to 5% of Nb and the balance cobalt. This alloy possesses a coercive force (Hc) of 10 to 50 Oe, a magnetic flux density (B.sub.100) of 10 to 17.5 KG., a squareness ratio (Br/B.sub.100) of not less than 0.70 and a fullness ratio of not less than approximately 0.70. The alloy material is also characterized by a good plastic workability.