Magnetically enhanced hard-soft SmCo5-FeNi composites obtained via high energy ball milling and heat treatment


The effect of high energy ball milling on the structure and magnetic properties of SmCo5-x%FeNi (x: 5, 15), magnetically hard-soft phase composites, has been investigated as a function of composition ratio, ball milling time, and annealing temperature using x-ray diffraction and room temperature magnetometry. The milling resulted in decomposition of SmCo 5 and FeNi phases. Heat treatment of ball-milled composites resulted in a secondary soft magnetic phase FeCo. High remanence and coercivity values are obtained at a low annealing temperature of ∼650 1C and short annealing time (20 min). Magnetic measurements of annealed composite sample, SmCo 5-5%FeNi, show enhancement in magnetization (178%), remanence (127%), and coercivity (67%) as compared to that of pure SmCo5. The enhancement in coercivity and remanence is attributed to the effective exchange coupling between hard SmCo5 and soft FeCo/FeNi phases. Overall better magnetic properties were presented by composites with low FeNi content. The facile synthesis process represents a general process toward SmCo5 based exchange-spring nanocomposites for high performance bulk permanent magnet.

Publication Title

Journal of Magnetism and Magnetic Materials