Microstructure and Performance of Mn-Ga/Fe-Cr-Co Magnetic Composites Fabricated by Mechanical Alloying

Mn-Ga and Fe-Cr-Co have potential use as components in exchange-coupled composite magnets. Herein, we prepared Mn-Ga composites through mechanical alloying, which was followed by sintering. During high-energy ball milling, Fe-Cr-Co powder was added into the Mn-Ga powder to form a composite. The main phases in the composites existed as pure Mn and pure Ga in the as-milled state; subsequently, these phases changed into intermetallic compounds, such as Mn 3 Ga and Mn 0.85 Ga 0.15 , after sintering at 385°C for 6 h. When the Fe-Cr-Co fraction increased from 0% to 20%, the coercivity ( H c ) of the Mn-Ga/Fe-Cr-Co composites decreased monotonically from 8.04 kOe to 2.28 kOe; furthermore, their remanence ( M r ) increased from 8.52 emu/g to 13.33 emu/g, and the maximum energy product (BH) max increased from 0.15 MGOe to 0.26 MGOe. The results obtained in this study facilitate the improvement of the magnetic properties of Mn-Ga composites for utilization in permanent magnet applications.