Magnetic properties and microstructures of high-performance Sm2Co17 based alloy

Precipitation-hardened Sm2Co17 based sintered permanent magnet has been attracting a great deal of attention by virtue of its distinguished high temperature magnetic properties, extremely low temperature coefficient, excellent corrosion resistance and oxidation resistance. Magnetic properties and microstructures of Sm2Co17 based sintered permanent magnets with the nominal composition Sm(Co(bal)fe(0.245)Cu(0.07)Zr(0.02))(7.8) have been investigated. The magnets referred were prepared using the conventional powder metallurgy method, where the techniques of making powder were ball-milling and jet-milling, respectively. The corresponding magnetic properties of the magnet made of ball-milling powder are the remanence B-r=1.157 T (11.57 kGs), the intrinsic coercivity H-cj=752 kA/m (9.46 kOe), and the maximum magnetic energy product (BH)(max)=221 kJ/m(3) (27.8 MGOe), while that of jet-milling powder are B-r=1.133 T (11.33 kGs), H-cj=2613 kA/m (32.83 kOe), and (BH)(max)=242 kJ/m(3) (30.4 MGOe). The cause of such a significant difference between the two is considered to be that the actual chemical compositions in micro zone are different, which is deemed to be related to the different actual chemical compositions due to the differences of oxygen content in the final magnets: similar to 2800 and similar to 1300 ppm. (C) 2014 Elsevier B.V. All rights reserved