Characterization of Ni₇₅Mo₂₅ Alloy Prepared by Mechanical Alloying and Heat Treatment

The process of Ni75Mo25powder synthesis via mechanical alloying (MA) was studied. Process was carried out from pure elements: Ni and Mo with a particle size under 150 μm. A ball-to-powder weight ratio and the rotational speed were 5:1 and 500 rpm, respectively. Oxidation was reduced by milling under an argon atmosphere. The milling process was performed during up to 60 hours. X-ray diffraction (XRD) and scanning electron microscopy techniques have been used to investigate resulting products. It was found that the particle sizes decrease with the increase in milling time. The resulting powder consists of metastable Ni(Mo) and Mo(Ni) solid solutions. Milled Ni75Mo25 powder was subjected to heat treatment at temperature of 773K, 973K and 1173K. As a result of annealing the formation of Ni4Mo and NiMo intermetallic phases was observed.