ABSTRACT
A major concern in the processing of metal powders by mechanical alloying/milling (MA/MM) is the nature and amount of impurities that get incorporated into the powder and contaminate it. The small size of the powder particles and consequent availability of large surface area, formation of fresh surfaces during milling, and wear and tear of the milling tools all contribute to contamination of the powder. These factors are in addition to the purity of the starting raw materials and the milling conditions employed (especially the milling atmosphere). Thus, it appears that powder contamination is an inherent drawback of the technique and that the milled powder will be always contaminated with impurities unless special precautions are taken to avoid or minimize it.
