(SmCo) Magnets
In comparison to Neodymium Iron Boron (NdFeB), Samarium Cobalt SmCo magnets are stronger and have less resistance to demagnetization. SmCo is also stronger and more resistant to corrosion, but it is less fragile. This alloy is a great option for motors that operate at high temperatures. It also has exceptional thermal properties that are unparalleled by rare earth magnets. These magnets are used in microphones, medical instruments magnetic separation devices and other applications.
SmCo has an extremely high coefficient of coercivity (or “coercive force”) which is a key factor in determining magnet strength and durability. The coefficient of coercivity for SmCo is between -0.03 and -0.05 percent per degree Celsius (C) that means that SmCo magnets lose more field strength with every degree of temperature rise. However, the SmCo temperature coefficient is only slightly higher than the NdFeB temperature coefficient.
Like all magnets, their strength and durability depend on how it is utilized in a magnetic circuit. If a magnetic device is used in an environment that is humid or acidic environment the magnet will lose its magnetic field more easily. Also, if a magnet is placed in reverse magnetic fields, it will lose its magnetic field. Due to the high coercivity and the heat required to demagnetize a SmCo magnet requires more heat than demagnetizing an NdFeB one.
Samarium Cobalt SMCo is a fantastic choice for high-temperature motor applications. The magnets are impervious to corrosion and maintain their temperature effectively. They also have a high coefficient of coercivity and are suitable for use in extremely cold conditions. The magnetic strength of SmCo is similar to that of Neodymium however, SmCo magnets are less reactive, making them more stable in challenging environments.
SmCo magnets come in two different series. The first series, called the 2:17 alloy, is composed of iron and cobalt. The second series is a mixture of cobalt, 5percent copper, and 5. The alloy has a higher temperature operating range than the first. The magnet can be operated at 350 degrees Celsius. SmCo magnets of the 2:17 series have an energy value of 24 MGOe up to 32MGOe.
SmCo is used for applications that require high temperatures, like medical instruments and magnetic separation devices. They are also used in permanent magnet motors that are high-performance. However they are more expensive than Neodymium Iron Boron magnets. They are also difficult to remove and require special handling and methods of machining. SmCo magnets are more susceptible to chipping than Neodymium magnets.
Samarium Cobalt SmCo magnets are available in different grades. Grades balance cost and performance. The more expensive the grade, the better the energy product. The 34 grade is the most expensive grade. It is an alloy which delivers the highest energy density at the small size. The energy product is guaranteed to be 29.5 MGOe, which is a significant improvement over NdFeB.
Samarium-cobalt magnets are also renowned for their excellent corrosion resistance and high temperature coefficients. Their tetragonal crystal shape gives them highly directed magnetic properties.