STUDY ON SmCo PERMANENT MAGNETS UNDER 350 MODERATE TEMPERATURES

Abstract

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℃.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℃.the magnets were found to have low magnetic properties at room temperature and 350℃.Thus,there is a demand for developing permanent magnet materials with high properties at moderate temperatures below 350℃.The effect of Fe and Cu contents on the magnetic properties of Sm(Co_(bal)Fe_xCu_yZr_(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_(bal)Fe_(0.20)Cu_(0.08)Zr_(0.03))_(7.5) alloy is expected for potential applications at moderate temperatures below 350℃.