Formation of ZnO/Ni_0.6Zn_0.4O Mixture Using Mechanical Milling of Zn-NiO

Abstract

Mixtures of Zn-NiO with stoichiometric compositions were milled for different times in open-valve milling cups. Although the gradual reduction of nickel oxide with zinc occurred during one hour of milling, it was found that nanometric mixtures of ZnO and Ni_0.6Zn_0.4O appear after 72000 seconds (20 hrs) of milling with the crystallite size of Ni_0.6Zn_0.4O phase being about 22 nm. On the other hand, and under the flow of argon gas, narrow and intense peaks of ZnO and Ni_0.6Zn_0.4O were observed after isothermal heating of 1800 seconds milled samples at 1273 K. Electron microscopy observations and elemental analysis of the products confirm formation of ZnO nano-needles distributed in the nickel zinc oxide matrix.