Bismanol is a magnetic alloy of bismuth and manganese (manganese bismuthide) developed by the US Naval Ordnance Laboratory.
History
Bismanol, a permanent magnet made from powder metallurgy of manganese bismuthide, was developed by the US Naval Ordnance Laboratory in the early 1950s – at the time of invention it was one of the highest coercive force permanent magnets available, at 3000 oersteds.[1] Coercive force reached 3650 oersteds and magnetic flux density 4800 by the mid 1950s. The material was generally strong, and stable to shock and vibration, but had a tendency to chip. Slow corrosion of the material occurred under normal conditions.[2]
The material was used to make permanent magnets for use in small electric motors.[3]
Bismanol magnets have been replaced by neodymium magnets which are both cheaper and superior in other ways, by samarium-cobalt magnets in more critical applications, and by alnico magnets.[citation needed]
References
- ^ "Bismanol", Physics Today. 5 (8): 19, August 1952, doi:10.1063/1.3067699
- ^ Adams, E. & Hubbard, W.M. (1953), "BISMANOL PERMANENT MAGNETS, EVALUATION AND PROCESSING", Naval Ordnance Lab., USA
- ^ Adams, Edmond (1953). "A New Permanent Magnet from Powdered Manganese Bismuthide". Rev. Mod. Phys.. 25 (1): 306–307. Bibcode:1953RvMP...25..306A. doi:10.1103/RevModPhys.25.306