Interfacial tension of Fe-Si liquid at high pressure: Implications for liquid Fe-alloy droplet size in magma oceans

Hidenori Terasaki, Satoru Urakawa, David C. Rubie, Ken ichi Funakoshi, Tatsuya Sakamaki, Yuki Shibazaki, Shin Ozawa, Eiji Ohtani

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The interfacial tension of Fe-Si liquid was measured using in situ X-ray radiography at high pressure and temperatures using the sessile drop method. The interfacial tension of Fe-Si liquid decreases (from 665 to 407. mN/m) with increasing temperature (1673-2173. K) at 1.5. GPa. The interfacial tension also decreases gradually with increasing Si content (0-25. at%), suggesting that Si behaves as a " moderately" surface-active element. Comparing the effects of different light elements on the interfacial tension of liquid iron, the most effective elements for reducing the interfacial tension lie in the order S. >. Si. >. P, although P has almost no effect. The droplet size of emulsified Fe-alloys in a magma ocean are estimated to be larger for Fe-Si and Fe-P liquids and smaller for Fe-S (S. >. 10. at%) liquid compared with that for pure Fe liquid. Therefore, if droplets in a magma ocean are enriched in S, chemical equilibrium between droplets and silicate melt is established faster in the magma ocean compared to Fe, Fe-Si and Fe-P liquids.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalPhysics of the Earth and Planetary Interiors
Publication statusPublished - Aug 1 2012



  • Fe-Si
  • High pressure
  • Interfacial tension
  • Magma ocean

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

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