Process control agent and time duration effects on milling of Aluminum powder

Commercially pure aluminum powder was milled for different periods of time in presence of different process control agents (PCAs), including ethanol, graphite and stearic acid. The morphology of powder particles was characterized quantitatively using optical microscopy (OM) and an image processing program. Normal distribution curves for morphological parameters of Feret diameter and aspect ratio were drawn. X-ray diffraction analysis was also employed to evaluate the crystallite size changes during the course of milling operation. Calculated crystallite sizes in particles of the milled powders indicated that they were indeed in nano-scale. The results show that the type of PCA used, is a much more effective parameter on morphology of powder particles in comparison with the milling time. Ethanol as a liquid PCA was found more effective comparing with other solid PCAs.

Quantitative morphology, PCA effect, Milling time, Feret diameter, Aspect ratio, Crystallite size