High temperature properties improvement and microstructure regulation of Sm2Co17-based permanent magnet

It is well known that the high temperature magnetic properties of traditional Sm2Co17-based magnets can be further improved through adjustment of chemical composition and technique process. The H-cj of Sm(CobalFe0.1Cu0.09Zr0.03)(z) (z=7.0-7.3) magnets fluctuate over a large range at the variation of Sm content, and Sm(CobalFe0.1Cu0.09Zr0.03)(7.2) magnet shows excellent magnetic properties as (BH)(max) of 22.5 MGOe, H-cj of 28.3 kOe and B-r of 9.65 kG at room temperature respectively. Meantime through optimization of solid solution conditions, the Sm(CobalFe0.1Cu0.09Zr0.03)(7.2) magnets possess excellent magnetic properties as B-r=7.22 kG, H-cj=7.6 kOe, (BH)(max)=11.6 MGOe at 500 degrees C. The beta (temperature coefficient of coercivity from room temperature to 500 degrees C) can be optimized to +0.1113%/degrees C from -0.134%/degrees C as quenching temperature increases from 420 degrees C to 830 degrees C, but H-cj deteriorates to 1.4 kOe from 28 kOe. Distribution of Cu content in cell boundaries for Sm(CobalFe0.1Cu0.09Zr0.03)(7.2) quenched at 420 degrees C and 830 degrees C was analyzed using TEM-EDS, the result indicates that distribution of Cu is the main reason to give rise to the variation of H-cj and beta.