Measurement of the surface tension of liquid Ga, Bi, Sn, in and Pb by the constrained drop method

The effect of the droplet size on the accuracy of surface tension measurement by the sessile drop method is discussed for liquid metals through a simulation by using the Laplace equation. It is found that with increasing size of the droplet, a higher accuracy of the measured value of the surface tension can be obtained. In order to make a large droplet of liquid metals, the constrained drop method with a special crucible shape was applied to measure the surface tension of liquid Ga, Sn, Bi, In, and Pb. The uncertainty of the measured surface tension was within 1 %. The temperature dependences of the surface tension of liquid Ga, Sn, Bi, In, and Pb were obtained in the present experiment as follows: Ga: σ_Ga = 737 - 0.062T mN/m (823 ≤ T ≤ 993K) Sn: σ_Sn = 579 - 0.066T mN/m (723 ≤ T ≤ 993K) Bi: σ_Bi = 417 - 0.070T mN/m (773 ≤ T ≤ 873K) In: σ_In = 600 - 0.082T mN/m (673 ≤ T ≤ 993K) Pb: σ_Pb = 499 - 0.089T mN/m (757 ≤ T ≤ 907K).