STRUCTURAL, SURFACE AND TRANSPORT PROPERTIES OF Sn-Ag ALLOYS

The structural, surface and transport properties of Sn-Ag alloys were investigated by X-ray diffraction (XRD), radial heat flow, energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM) and four-point probe techniques. We observed that the samples had tetragonal crystal symmetry except for the pure Ag sample which had cubic crystal symmetry, and with the addition of Ag the cell parameters increased slightly. Smooth surfaces with a clear grain boundary for the samples were shown on the SEM micrographs. The grain sizes of pure Ag, beta-Sn and the formed Ag3Sn intermetallic compound phase for Sn-x wt.% Ag [x=1.5, 3.5] binary alloys were determined to be 316nm, between 92 nm and 80 nm and between 36 nm and 34 nm, respectively. The values of electrical resistivity for pure Sn, pure Ag and Sn-x wt.% Ag [x=1.5, 3.5] were obtained to be 22.60x10(-8), 62.36x10(-8), 23.54x10(-8), 24.62x10(-8) Omega.m at the temperature range of 300-450K, respectively. Thermal conductivity values of pure Sn and Sn-x wt.% Ag [x=1.5, 3.5] binary alloys were found to be 60.60 +/- 3.75, 69.00 +/- 4.27 and 84.60 +/- 5.24 W/Km. These values slightly decreased with increasing temperature and increase with increasing of the Ag composition. Additionally, the temperature coefficients of thermal conductivity and electrical resistivity and the Lorenz numbers were calculated.