Use of cobalt - alloys for permanent magnets with a high coercive force

摘要

Permanent magnet alloys consisting of, in percentage by weight TABS:1087064/C6-C7/1 and which may have been produced either by sintering or casting are heat-treated to precipitate fine ferro-magnetic particles of zeta-phase in a non-magnetic matrix of epsilon-phase. The heat treatment may consist of (a) chill casting the alloy and subsequently heating it to a temperature above 200 DEG C. (b) solution treating the alloy, quenching, and subsequently heating to a temperature above 200 DEG C. (c) cooling the alloy, either immediately following casting or from the solution treatment temperature, at such a rate that the desired precipitate is formed. As exemplified solution treatment is carried out at 1180 DEG -1400 DEG C. and precipitation treatment at 400 DEG -800 DEG C. for 30 minutes to 300 hours. In the production of the alloys by sintering, powdered alloys containing 70% Co/30%Al, 70% Co/15% Al/ 15%V, and 55% Co/3% Al/40% Sn were first prepared; to these powders as appropriate were added metal powders to obtain the desired composition. Ether was added and, after mixing, the powders were moulded at about 18 tons/sq. in. for 10 seconds, after which the resulting compacts were sintered at 1300 DEG -1380 DEG F. for 1 to 3 hours.