Bismanol is an 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 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Bismanol magnets have been replaced by Neodymium magnets which are both cheaper and superior in other ways, Samarium-Cobalt magnets in more critical applications, and Alnico magnets.^{[citation needed]}