Determination of interdiffusion coefficients of liquid zinc and tin under convectionless conditions

In this paper we present a new method for measuring diffusion coefficients in liquid metals under convectionless conditions with solid/liquid–liquid/solid trilayers. The advantage of this kind of trilayer is that effects from gravity-induced convection and Marangoni convection can be omitted, so that the diffusion coefficient is determined more accurately. The Ta/Zn-Sn/Si trilayers were prepared with a multi-target ion-beam sputtering deposition technique and annealed in an electric furnace under an argon atmosphere. The interdiffusion of liquid zinc and tin at 500 °C was investigated. The diffusion concentration profiles were determined by energy dispersive spectroscopy. The interdiffusion coefficients range from 1.0×10-6 cm2/s to 2.8×10-6 cm2/s, which is less than previous values measured by capillary reservoir technique under 1–g environment where various convections exist. The precise interdiffusion coefficients of liquid zinc and tin result from the removing of disturbances of various kinds of convection.