High temperature magnetic property of Sm(Co_balFe_0.1 Cu_0.1Zr_0.04)_z (z=6.5-7.5) magnets

There is a great demand for high temperature permanent magnet materials which are over 450°C in temperature and can be used in high-power generators in the field of aviation. However, the temperatures for use of NdFeB permanent magnet materials are lower than 80°C. Even high temperature NdFeB permanent magnet materials can only be used at temperatures lower than 150°C. The temperature range of 2:17-Sm₂Co₁₇ permanent magnets for business use is below 300°C. In recent years, the development of high temperature permanent magnetic materials with using temperatures exceeding 450°C has become a hot issue in the field of study. In this article the Sm(Co_balFe_0.1 Cu_0.1Zr_0.04)_z (z=6.5~7.5) alloys are prepared by powder metallurgy. The effect of z value on the structure and magnetic properties of Sm(Co_balFe_0.1 Cu_0.1Zr_0.04)_z alloys is studied. The highest room temperature intrinsic coercivity iHc is achieved at more than 2400 kA/m for z=7.3. A coercivity of more than 640 kA/m is obtained at 773 K for z=7.1. The temperature coefficient of coercivity is -0.052%/°C for z=6.9. The temperature coefficient of coercivity increases for z≤6.7 or z≥7.1.