Effect of Mn additive on the Structure and electrochemical properties of nano-crystalline Mg2Cu- based intermetallic compound produced by mechanical alloying

Mechanical alloying of powder mixtures with initial chemical compositions of Mg2-xMnxCu (x=0, 0.15, 0.25) has been carried out for the synthesis of nano-crystalline powder based on Mg2Cu intermetallic compound with Mn additives. Characterization of the crystal structure of the milled products using X-ray diffractometry exhibited the formation of Mg2Cu based nano-crystallites after 10 and 5 milling hours for binary and ternary powder mixtures respectively. The calculated mean Mg2Cu crystallite size was found to be 3.961, 5.73 and 3.984 nm. After 35 h of milling for the initial powder mixture of Mg2Cu, Mg1.85Mn0.15Cu and Mg1.75Mn0.25Cu, respectively. The development of the amorphous structure in Mg2Cu alloy was very fast and the maximum storage capacity was reached at 25 h ball milling. Both the initial discharge capacity and capacity retention rate of Mg2Cu alloy were much better compare to those of ternary alloys.

Keywords:

Mechanical alloying , Intermetallic compound , Mg2Cu , Nano-crytallites , Mn