Narrow Results

SiC-mixed Sn–58Bi composite solder bumps were successfully fabricated via an electroplating process. For the composite solder bump fabrication, ultrasonically dispersed SiC nanoparticles were added to the plating solutions. DSC analysis indicated that the melting temperature of SiC-mixed Sn–58Bi solders was the same as that of the non-mixed Sn–58Bi. Shear strengths of Sn–58Bi+SiC solder bumps were 6% higher than that of non-mixed solder bumps. The thicknesses of intermetallic compound were almost the same for both Sn–58Bi and Sn–58Bi+SiC samples. The Sn–58Bi+SiC composite solder bumps had finer lamellar structures than non-mixed Sn–58Bi. From the fracture surface analysis, fracture occurred at solder bump matrix, not at joint interface. Therefore, the addition of the SiC nanoparticles in the Sn–58Bi solders decreased the grain sizes, which increased the shear strengths.

The surface tension and viscosity in the liquid Cu-Ag-In ternary alloys have been estimated using Muggianu and Toop geometric models and Seetharaman–Sichen equations, respectively along a cross-section of $x_{\mathrm{\text{Ag}}}$/$x_{\mathrm{\text{In}}}=1∕2$, 1/1 and 2/1. The surface tension has also been estimated using Butler equation. In addition, the enthalpies of the same ternary alloys have been predicted at different temperatures along five cross-sections $x_{\mathrm{\text{Cu}}}$/$x_{\mathrm{\text{In}}}=1∕3$, 1/2, 1/1, 2/1 and 3/1 using Kohler, Toop and Chou models. The geometric models are used in this work in order to verify their effectiveness since they are considered as the most widespread theoretical models used for metallic alloys. The estimated values obtained show that the surface tension decreases with increasing temperature for the all studied models and equations and increase with increasing copper-composition, except for few Cu-compositions where an opposite tendency is observed. It should be noted that the surface tension has a negative and positive temperature coefficient (d$\sigma$/d$T)$. The viscosity decreases with increasing temperature but increases with increasing copper-compositions. The calculated surface tension and enthalpy of mixing of the investigated system are compared with the reachable experimental data and a relatively excellent accord was obtained.

In this paper, the surface tension, molar volume and density of liquid Ag–Cu–Sn alloys have been calculated using Kohler, Muggianu, Toop, and Hillert models. In addition, the surface tension and viscosity of the Ag–Cu–Sn ternary alloys at different temperatures have been predicted on the basis of Guggenheim and Seetharaman–Sichen equations, respectively. The results show that density and viscosity decrease with increasing tin and increasing temperature for the all studied models. While the surface tension shows a different tendency, especially for the Kohler and Muggianu symmetric models. On the other hand, the molar volume increases with increase of temperature and tin compositions. The calculated values of surface tension and density of Ag–Cu–Sn alloys are compared with the available experimental values and a good agreement was observed.

In this paper, some geometrical models such as Kohler, Muggianu, Toop, and Hillert have been used to estimate the molar volume of Au–Bi–Sn ternary systems based on the data of sub-binary systems over a wide temperature range (673–973K). The density of Au–Bi–Sn alloys was calculated from the calculated molar volume and using theoretical equation along three cross-sections $x_{\mathrm{\text{Au}}}$/$x_{\mathrm{\text{Bi}}}=1$/2, 1/1 and 2/1. In addition, the viscosity of Au–Bi–Sn alloys was calculated by using Seetharaman–Sichen equation over a wide temperature range (673–1273K). The density of these alloys show linear dependence on temperature for all investigated compositions, while the molar volumes increase with increasing temperature and Sn compositions. The results show, as a function of temperature, that the increase in concentration of tin influences the viscosity of the Au–Bi–Sn alloys. The calculated values of density of Au–Bi–Sn alloys are compared with the experimental values reported in the literature, and a good agreement was observed.

Some physicochemical properties such as surface tension, molar volume, density and viscosity of liquid Sn–Ag–Cu alloys have been calculated using Kohler, Muggianu, Toop and Hillert geometrical models along three cross-sections namely $x_{\mathrm{\text{Ag}}}$/$x_{\mathrm{\text{Cu}}}=1∕2$, 1/1 and 2/1. Indeed, Guggenheim, Kozlov–Romanov–Petrov and Kaptay equations have also been extended to estimate the surface tension and viscosity based on the thermodynamic data of the investigated system over wide temperature ranges of 823–1123K and 773–1173K, respectively. The results show that the three investigated properties, surface tension, density and viscosity, decrease with increasing tin for all studied models. On the other hand, a different behavior of these properties as a function of the temperature was noted. This evolution depends on the composition of the studied alloys.

On the contrary, the molar volume increases with increase of temperature and tin compositions. It should be noted that the surface tension, density and molar volume show a linear dependence on temperature for all the investigated compositions. For viscosity, a curvilinear dependence has been observed. The calculated surface tensions and densities were compared with those reported experimentally for Sn–Ag–Cu alloys along the cross-section $x_{\mathrm{\text{Ag}}}$/$x_{\mathrm{\text{Cu}}}=$1/1.