Bismanol

Bismanol is an magnetic alloy of bismuth and manganese (manganese bismuthide) developed by the US Naval Ordnance Laboratory.

Bismanol
Identifiers
Properties
BiMn
Molar mass 263.91844 g·mol−1
Structure
NiAs type
R3m[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.[2] 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.[3]

The material was used to make permanent magnets for use in small electric motors.[4]

Bismanol magnets have been replaced by neodymium magnets which are both cheaper and superior in other ways, by samarium-cobalt magnets in more critical applications, and by alnico magnets.

References
  1. Yang, J B; Yelon, W B; James, W J; Cai, Q; Kornecki, M; Roy, S; Ali, N; l$rquot$Heritier, Ph (2002). "Crystal structure, magnetic properties and electronic structure of the MnBi intermetallic compound". Journal of Physics: Condensed Matter. 14 (25): 6509–6519. doi:10.1088/0953-8984/14/25/318. ISSN 0953-8984.
  2. "Bismanol", Physics Today, 5 (8): 19, August 1952, doi:10.1063/1.3067699
  3. Adams, E.; Hubbard, W.M. (1953), "BISMANOL PERMANENT MAGNETS, EVALUATION AND PROCESSING", Naval Ordnance Lab., USA, OSTI 4290472
  4. 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.
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