SmCo magnet ditches rare earth elements

Article By : Vivek Nanda

Toshiba has developed a samarium-cobalt magnet for industrial motors that is resistant to demagnetisation at high temperatures yet is free from rare earth elements.

Traction motors for hybrid and electric automobiles, railroad rolling stock and the motors for industrial equipment and wind turbines operate at high temperatures, wherein heat-resistant neodymium magnets are generally used.

Neodymium magnets operate with much magnetic force at room temperature, but heat-resistant as they are, they fall short in high-temperature applications as their torque declines. To compensate for this, neodymium magnets are replaced with rare earth elements such as dysprosium and telbium, which cannot guarantee stable magnetism during operation. Moreover, the heavy rare earth elements are expensive and in short supply.

A magnet at 180°C

Toshiba Corp. and Toshiba Materials Co. Ltd have developed an iron-concentrated samarium-cobalt magnet that is resistant to demagnetisation and is free from rare earth elements.

Toshiba began by developing iron-concentrated samarium-cobalt magnet, which outperformed neodymium magnets during testing. The samarium-cobalt magnet showed to be 1% more magnetic than the other at 100°C and 5% at 150°C.

Now, the company is offering a version of the samarium-cobalt magnet that has demagnetisation resistance at 180°C and a higher coercivity than the 2012 version. With the higher heat resistance, it can be used in designing simple cooling systems for industrial equipment with integrated motors.

Toshiba used a heat-treatment technology that has increased the magnetic force of its samarium-cobalt magnet, which can be used in motors for automobiles, locomotives, machine tools, and elevators.

Toshiba Materials is sampling the new magnet.

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