Samarium Cobalt Magnets
Samarium Cobalt Magnets are strong rare earth magnets made from an alloy of samarium and cobalt, and its main advantage is very high working temperature. Their magnetic force is measured on a scale of 16MGOe-32MGOe. They have been available since the early 1970s, and opened the door towards the development and commercial use of Neodymium. This sort of rare earth magnet is very powerful; however, it is also very brittle and prone to cracking and chipping, so it must be handled with care and adequate protective gear. Due to its relative frailty, mechanisms and applications in which the magnet is used must be adapt and designed to support the material.
SmCo is highly coercive. Its coercive field is considerably more resistant to demagnetization than that of Neo magnets. This quality makes for an extremely trustworthy magnet, but also requires additional cautionary measures during plating- magnets can pick up small fragments which disrupt the coating process.
Although more expensive than and not as strong as Neodymium magnets – Samarium Cobalt magnets have a higher Curie temperature and can be used for extreme temperature applications, including cryogenic ones.
Some ores of Samarium Cobalt contain Copper and Iron, and by adding Zirconium- magnets can increase their heat resistance.
This trade makes SmCo magnets desirable for applications in the Military and Space industries.
Pro & cons of Samarium Cobalt Magnets
- High resistance to demagnetization.
- High resistance to corrosion. No coating required.
- High energy (magnetic strength is strong for its size).
- Good temperature stability (maximum use temperatures between 250°C and 550°C; Curie temperatures from 700°C to 800 °C).
- Relatively expensive (Cobalt is market price sensitive).