Bismanol
Chemical compound
From Wikipedia, the free encyclopedia
Bismanol is a magnetic alloy of bismuth and manganese (manganese bismuthide) developed by the US Naval Ordnance Laboratory.
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CompTox Dashboard (EPA) |
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| Properties | |
| BiMn | |
| Molar mass | 263.91844 g·mol−1 |
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| Melting point | 262 °C [2] Decomposes at ~335 °C (peritectic formation of MnBi)[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.[3] 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.[4]
The material was used to make permanent magnets for use in small electric motors.[5]
Bismanol magnets have been replaced by neodymium magnets which are both cheaper and superior in other ways, by samarium-cobalt magnets in more critical applications, and by alnico magnets.[citation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]