Study of structural changes and properties of some Sn-Ag lead-free solder alloys

¹ Metal Physics Lab., Faculty of Science, Mansoura University, Mansoura, Egypt
² Department of Solid State Physics, Metallurgy Lab., Physics Division, National Research Center, Dokki, Giza, Egypt

Corresponding author: gouda.el73@yahoo.com

Received: 4 July 2007
Revised: 10 August 2007
Accepted: 28 August 2007
Published online: 31 October 2007

Abstract

Structure, wetting, mechanical and electrical transport properties of tin- (2.5, 3.5, 5 and 10) wt.% silver alloys have been investigated. The results showed that, addition of silver to pure tin causes more precipitations of the intermetallic compound Ag₃Sn. A new intermetallic compound Ag₄Sn has been formed with adding Ag more than 3.5 wt.%. This compound causes continuous increase in the Young's modulus and electrical resistivity. While for the wetting measurements, additions of silver to pure tin up to 5 wt.% reduces the contact angle. Above that, the contact angle increases due to more precipitations of Ag–Sn compounds, which may tend to reduce the adhesive forces between molten alloys and the substrate.