Synthesis of Sn-Ag binary alloy powders by mechanical alloying

Sn-Ag binary powders of 2-5 wt%Ag were synthesized by mechanical alloying. Structural evolutions, morphologies, particle size distributions and melting points of the milled Sn-Ag powders were studied. The results show that the milled Sn-Ag powders consist of a supersaturated solid solution of Ag in Sn, Sn(Ag), and Ag3Sn. During ball milling, Sn, Ag particles in the Sn-3.5Ag powders are deformed, overlapped and cold-welded together to form the Sn/Ag composite particles with a lamellar structure, and then the composite particles are fractured into small spherical particles. When increasing the Ag content from 2 to 5 wt%, the average particle sizes of the 60 h milled Sn-Ag powders are changed from 2.2 to 5.7 mu m, and the morphologies of them are changed from spherical shape to irregular shape, respectively. It indicates that the cold-welding and agglomeration of the Sn-Ag powders increases with the Ag content during MA. The melting point of the 60 h milled Sn-3.5Ag powders was detected to be 224.23 degrees C, near to the eutectic point of the Sn-Ag binary system (221 degrees C). (C) 2010 Elsevier B.V. All rights reserved.