Long-term aging of Sm2(Co,Fe,Cu,Zr)17 permanent magnets at 300 and 400°C

Long-term aging experiments were carried out for Sm₂(Co,Fe,Cu,Zr)₁₇ permanent magnets at 300 and 400°C and both traditional and application-oriented characterizations were performed. Results of application-oriented characterizations show that the maximum energy product of the magnet at 300°C dropped ~10% after aging at 300°C for 9200 hours. Further, the maximum energy product of the same magnet at 400°C dropped ~43% after aging at 400°C for 4300 hours. The findings also indicate that the thermal stability of Sm₂(Co,Fe,Cu,Zr)₁₇ magnets is extremely sensitive to their iron content in the magnet alloys. It is anticipated that the high temperature performance of Sm ₂(Co,Fe,Cu,Zr)₁₇ magnets can be significantly improved by decreasing their iron content