Synthesis of MgB2 from Anhydrous B203 by Ball Milling Method and Determination of Superconductivity Properties

The discovery of superconductivity at 39 K in magnesium diboride (MgB2) has attracted much attention from theoretical and experimental points of view because it has the highest superconducting transition temperature in the conventional intermetallic superconductors reported so far. After the discovery of superconductivity in MgB2, many attempts have been made to synthesize this material with an aim of improving superconducting properties. In this study, MgB2 was synthesized from anhydrous B203. To provide homogeneous mixing of magnesium and boron oxide powders and to make easy sintering, powders were mechanically milled in an attritor under argon gas atmosphere. The mixture was treated with ethylenediamine solution to separete MgB2 from the product. The suspension solution was filtrated under vacuum and the solid particulates of MgO were removed. The filtrate was evaporated in a vacuum oven at 80 deg C and sintered at 900 deg C for 2 h under flowing argon gas atmosphere. XRD results showed that the final product was MgB2 with a small amount of MgO. Mechanical milling decreased the synthesis time and temperature of MgB2. The critical temperature of the specimens was determined as 37.4 K by an A.0 susceptometer.