《Surface Tension Measurements of the Bi-Sn and Sn-Bi-Ag Liquid Alloys》.pdfVIP

Journal of ELECTRONIC MATERIALS, Vol. 30, No. 9, 2001 1104 Special Issue Paper Moser, Gasior, and Pstrus Surface Tension Measurements of the Bi-Sn and Sn-Bi-Ag Liquid Alloys Z. MOSER, W. GASIOR, and J. PSTRUS Polish Academy of Sciences, Institute of Metallurgy and Materials Science, 30-059 Kraków, Reymonta Street 25, Poland The maximum bubble pressure method has been used to measure the surface tension of pure Bi, surface tension and density of liquid binary Bi-Sn alloys (XBi = 0.2, 0.4, 0.6, and 0.8 molar fractions) at the temperature range from about 500 K to 1150 K. Similarly, there were investigated ternary alloys adding to the eutectic (3.8\at.%Ag-Sn) 0.03, 0.06, 0.09, and 0.12 molar fractions of Bi. The linear dependencies of densities and surface tensions on temperature were observed and they were described by straight-line equation. It has been con- firmed that the additions of Bi to liquid Sn and to the eutectic alloy (3.8at.%Ag- Sn) markedly reduce the surface tension. Experimental data of the surface tension of liquid Bi-Sn were compared with modeling based on Butler’s method and a reasonable agreement was observed. Key words: Pb-free solders, surface tension, density of Bi-Sn and Ag-Bi-Sn, Butler’s method INTRODUCTION models. The one usually accepted is the Butler’s4