Synthesis of Ni–Y2O3 nanocomposite powders by a very high speed planetary milling process: Microstructural development and refinement behavior

Abstract

Abstract In the present work, Ni–Y 2 O 3 nanocomposite powders were synthesized in-situ using a very high speed planetary ball milling process; their microstructure and refinement behaviors were investigated as functions of milling speed and time. At a very high milling speed of 1000 rpm, the resultant composite powders were extremely blended and homogenized, forming a purely monoclinic Y 2 O 3 with a size of ~ 10 nm; these results were achieved within an hour. Moreover, it was notable that the original coarse cubic Y 2 O 3 particles were predominantly transformed into the monoclinic phase as milling time went by. On the other hand, at a conventional milling speed (~ 400 rpm), the limits of refinement were deemed to have been reached in terms of phase transition and homogenization of the particles, even for a long milling time of up to 240 min.