Study on SmCo permanent magnets under 350°C moderate temperatures

The magnetic properties of commercial 2:17-type SmCo magnet are low at high temperature, despite good properties at room temperature, therefore its application temperature is usually lower than 300°C. In recent years, significant progress has been made on the development of SmCo permanent magnets for high temperature applications. Despite the maximum operating temperature being up to 500°C, the magnets were found to have low magnetic properties at room temperature and 350°C. Thus, there is a demand for developing permanent magnet materials with high properties at moderate temperatures below 350°C. The effect of Fe and Cu contents on the magnetic properties of Sm(Co _balFe _xCu _y Zr _0.03) _7.5 (x=0.16-0.28, y=0.06, 0.08) magnets at room temperature and 350 have been systematically studied. The results show that with increasing Fe content, the intrinsic coercivity _iH _c gradually increases, reaching an optimal value of 2473 kA/m, and then drops rapidly at room temperature; the remanence B _r rises monotonically with increasing Fe content. The intrinsic coercivity _iH _c increases with raising Cu at a constant Fe content. The absolute value of temperature coefficient of coercivity |β| rises monotonically with increasing Fe content, and decreases with increasing Cu content. Sm(Co _balFe _0.20Cu _0.08 Zr _0.133) _7.5 alloy is expected for potential applications at moderate temperatures below 350.