How surface tension is measured for molten metals?

[ORF]

Hello

How the surface tension is measured for molten metals? I have heard about the sessile drop, but it seems to be a very inaccurate method...

Thank you for your time.

Regards.

 

[Mapes]

Experimentalists have also looked at the size of a drop as it falls (e.g., the pendant-drop approach, J Tille and J C Kelly 1963 Br. J. Appl. Phys. 14 717), the maximum bubble pressure method, electrostatic levitation of oscillating droplets, and characterization of oscillating droplets in microgravity (I Egry, G Lohoefer, and G Jacobs 1995 Phys. Rev. Lett. 75, 4043). The penultimate method seems to be the consensus for Earth-based characterization of the surface tension of molten metals and strongly reactive substances. The final method provides a check against the methods used to correct for the influence of the strong EM field required for levitation.

 

[Buzz Bloom]

I have heard about the sessile drop, but it seems to be a very inaccurate method...

Hi ORF:

A long time ago I was involved in helping a physical chemist friend determine surface tension of mercury drops by developing a method of calculating the best fitting mathematical shape of a sessile drop to a set of observed shape measurements. As I remember, the paper that resulted reported an acceptable level of precision in he results.

"A curve fitting method for calculating interfacial tension from the shape of a sessile drop" James N. Butler and Burton H. Bloom, Surface Science 4 (1966) 1-17.​

Why do you think this method is inaccurate?

Regards,
Buzz