Effect of Microstructure on the Coercivity of SmCo₅ Intermetallic Compound

Abstract

SmCo₅ is well known for its high coercive properties. This property helped the compound to become stable even at high temperatures. A lot of efforts had been made to improve this important property but so far only a few percentages of the theoretical coercivity values were achieved. Improving processing parameters or doping by other alloying elements are two popular ways to manipulate the properties of SmCo₅. In this research work, the cooling temperature of the indigenously developed water-cooled copper mold was manipulated to control the solidifying peritectic structure. The obtained casting was milled to powder and the final sintered product was produced. It was noted that high coercive values i.e. 32.9 kOe was achieved at low water inlet temperature. The results were interpreted by using a scanning electron microscope (SEM), Differential thermal analysis and X-Ray diffraction analysis. SEM results revealed peritectic nano-structure in SmCo₅ compounds. These nano-structures seem helped to improve the coercivity of SmCo₅.

Fig. 7 M-H curves comparing the magnetic properties of three samples i.e. Fast cooled, medium cooled and slow cooled.