How are Samarium Cobalt (SmCo) magnets manufactured?
How are samarium cobalt (SmCo)
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Samarium cobalt magnets are made from an alloy of samarium and cobalt. To create SmCo magnets, manufacturers usually follow these steps: | |||
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Step 1 – Strip castingFirst, the two materials are ground up and melted in a large oven at 14426.7°C (26000°F). When they are cool, the metals are all mixed together to create small chips. |
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Step 2 – MillingThe small chips of metal compound are ground down to a fine powder and mixed together thoroughly in a ball mill. |
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Step 3 – MouldingThe powder is then weighed and pressed into the moulds, which can be any shape of magnet. |
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Step 4 – PressingThe moulds are placed into a pressing machine which places a total of 21000psi of pressure onto them. |
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Step 5 – SinteringThe shaped metal is then placed into an electric oven, which heats the metal compound gradually from 250°C (482°F) to 900°C (1652°F). |
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The magnets can take from 20 to 36 hours to be heated depending on the quality of the end magnet. A top quality magnet will take a lot longer in the oven than a low quality one, as a slower temperature rise will produce a greater magnetic force.
For more information on sintering, see the |
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Step 6 – MachiningAfter the magnets have been removed from the oven and left to cool, they are ground down to the correct size. A diamond-coated machine takes off millimetres of metal until the required size is achieved. |
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They need to be machined with a constant flow of water due to the heat created in the machining process. | |||
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Step 7 – CoatingThe magnets are then coated to prevent them from oxidising. For more information on the types of plating and coatings, see the page: |
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Step 8 – MagnetisingFinally, the alloy is magnetised. A magnetising machine envelops the magnet in a high strength magnetic field by sending 2400 volts of electrical current through it to create a permanent samarium cobalt magnet. |
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