Mechanical alloying of NiNb in different atmospheres

Abstract

The formation of NiNb alloys prepared by mechanical alloying (MA) in different atmospheric conditions was examined by X-ray diffraction. Ball milling of elemental Ni and Nb powders under an argon atmosphere for alloys with Nb contents up to 15 at.% forms a supersaturated solid solution on the base of Ni. Amorphous alloys are formed if the Nb content is more than 20 at.%. The interaction of metallic powders Ni and Nb was absent and a b.c.c. phase was formed for all compositions up to pure Nb, when MA of NiNb powders was performed in the presence of water, alcohol or acetone in Ar and air atmospheres. This phase, identified as the interstitial phase of oxygen in niobium, has the lattice parameter a = 3.390 A ̊ and an O content of about 34 at.%.