EFFECT OF CARBON ADDITION ON THE SYNTHESIS OF Mg2Ni-BASED NANO-CRYSTALLINE POWDER USNGHGH ENERGY BALL, MLLNG

High energy ball milling of ternary powder mixture with stoichiometric compositions of Mg1.9NiCo, Mg17NiCo.2 and Mg1.5NiCo.5 has been carried out under an atmosphere of pure argon for the synthesis of nano-crystalline powders based on Mg2Ni intermetallic compound. A planetary ball mill was employed using a ball to powder weight ratio of 20:1 for various milling time of 5, 10 and 20 hours. Characterization of the crystal structure of the milled products using X-ray diffractometry exhibited the formation of Mg2Nibased nano-crystallites after ~5h for the initial mixture with stoichiometric composition of Mg2Ni and Mg1.9NiCol. However, Mg2Nibased nano-crystallites were synthesized after 15 and 20h of milling in the case of Mg17NiCo.2 and Mg3NiCos, respectively. The results show that increasing the carbon content of initial powder mixture decreases the formation kinetics of Mg2Ni-based nanocrystallites. In addition, increasing milling time resulted in decreasing and increasing the mean crystallite size and lattice strain of Mg2Nistructure in all milled products.

کلیدواژه ها:

. Mg2Ni ، nano-crystalline ، high energy ball milling ، c