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How are Samarium Cobalt magnets made?

Samarium cobalt magnets have now been widely produced for 40 years. The permanent magnets are primarily made up of samarium and cobalt but some grades will also contain varying small amounts of iron (Fe), copper (Cu), hafnium (Hf), zirconium (Zr) and praseodymium (Pr).

Did you know?
Samarium cobalt magnets have been produced for over 40 years.

A number of common manufacturing processes can be used to produce samarium cobalt magnets but typically, a method of reduction and melting is used followed by a process of bonding or sintering the raw material to form the magnet.


Did you know?
Samarium cobalt magnets can be manufactured using either a bonding or sintering process.


Firstly, the raw materials required to produce a samarium cobalt magnet are heated in an induction furnace filled with argon gas and melted to form the alloy material.


Next, the liquid alloy is then poured into moulds and cooled with water to form ingots. Once the ingots have cooled they are then broken down, ground and milled to produce tiny particles.


As an alternative to sintering, the alloy powder is mixed with a binding chemical such as an epoxy resin, die pressed and heated in the presence of an externally applied magnetic field to orientate the particles. As a result, most bonded samarium cobalt magnets are anisotropic but typically have a lower maximum energy value than sintered samarium cobalt magnets.


Typically, bonded samarium cobalt magnets don’t require any additional machining as they are pressed into their desired form. The final step is for the magnets to be coated if a coating is required and then magnetised using an externally applied magnetic field.


The first two steps for creating sintered samarium cobalt magnets are identical to the first two steps in manufacturing the bonded form. The process differs at step three, where we will pick up here:


As an alternative to bonding the alloy particles using a binding chemical, the powder is pressed into a die and sintered at a temperature up to 1250?C, fusing the powder into a solid. The sintered material is then given a solution treatment at similar temperatures before being tempered between 700?C and 900?C, and then cooled in the presence of an externally applied magnetic field.


The final process in manufacturing a sintered samarium cobalt magnet is machining and grinding. Unlike the bonded form, a level of grinding and finishing is required and must be done using water-cooled diamond-coated grinding machinery as the material is very hard and brittle and the dust produced highly flammable. The formed magnet is then coated and magnetised.

Finally, every magnet sold by is quality assured before it is dispatched to the customer to be used in hundreds of different applications.