Surface tension of superheated and undercooled liquid Co–Si alloy

Abstract

The surface tension of superheated and undercooled liquid $\mathrm{Co}$ $25\mathrm{wt.}\%$ $\mathrm{Si}$ alloy was measured by an electromagnetic oscillating drop method. The experimental temperature regime was from 1384 to $2339\mathrm{K}$ and a maximum undercooling of $223\mathrm{K}$ $\left(0.14T_{\mathrm{L}}\right)$ was achieved. The surface tension of liquid $\mathrm{Co}$ $25\mathrm{wt.}\%$ $\mathrm{Si}$ alloy is $1.604{\mathrm{Nm}}^{-1}$ at the liquidus temperature of $1607\mathrm{K}$ , and its temperature coefficient is $-4.0\times {10}^{-4}{\mathrm{Nm}}^{-1}{\mathrm{K}}^{-1}$ . On the basis of previous research results of pure $\mathrm{Co}$ and $\mathrm{Si}$ , an expression is developed to predict the surface tension of binary $\mathrm{Co}–\mathrm{Si}$ alloy system. The other thermophysical properties, such as the viscosity, the solute diffusion coefficient, and the density of liquid $\mathrm{Co}$ $25\mathrm{wt.}\%$ $\mathrm{Si}$ alloy are also derived by the relevant theoretical models.