Samarium-cobalt permanent magnets belong to the second generation of rare-earth permanent magnet materials. Composed primarily of samarium and cobalt, they possess unique high-temperature stability and corrosion resistance. Compared to neodymium-iron-boron magnets, samarium-cobalt magnets perform better in high-temperature environments:
Their Curie temperature and maximum operating temperature range from 250 to 350°C, and they maintain good magnetic stability even at temperatures above 180°C. Additionally, samarium-cobalt has an extremely low temperature coefficient, resulting in minimal magnetic flux decay due to temperature changes; the material itself is resistant to oxidation and corrosion, eliminating the need for protective electroplated coatings, unlike neodymium-iron-boron. Furthermore, samarium-cobalt possesses a high intrinsic coercive force and is highly resistant to external magnetic field interference and high-temperature demagnetization. These characteristics make it the best choice among current high-temperature permanent magnet materials. Since their introduction in the 1970s, samarium-cobalt magnets have been used in aerospace, defense, microwave devices, communications, and medical equipment—fields that require magnetic stability under harsh conditions.
In specific applications for humanoid robots, the advantages of samarium-cobalt magnetic materials are increasingly being recognized. In particular, samarium-cobalt magnets are the ideal choice when robot motors must operate at high temperatures or under prolonged heavy loads while requiring an extremely low risk of demagnetization.
Case studies show that the waist rotation motor of a humanoid robot uses samarium-cobalt magnets capable of withstanding temperatures above 200°C to ensure posture control accuracy of 0.01° even under heat-generating operating conditions. This practical application demonstrates that incorporating samarium-cobalt magnets into high-torque robot joints (such as the waist and hips) or areas with limited heat dissipation can effectively prevent magnet demagnetization caused by motor temperature rise, thereby ensuring the reliability and precision of robot operation. When humanoid robots are deployed in high-temperature environments (such as fire rescue or smelting operations) or require prolonged continuous operation, the high-temperature resistance and demagnetization resistance of samarium-cobalt magnets become even more prominent.
As the penetration rates of industrial and service robots increase, demand for more reliable magnetic materials will be stimulated, which is expected to drive growth in the market for samarium-cobalt permanent magnet materials. Although the current market size for samarium-cobalt magnets is relatively small (China’s consumption of samarium-cobalt magnets was approximately 0.2 metric tons in 2022), their irreplaceable performance in specific high-end applications makes them a strategic, future-oriented supplementary material.
