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Surface Tensions and Their Variations with Temperature and ImpuritiesThe surface tensions in this work were determined using the sessile drop technique. This method is based on a comparison of the profile of a liquid drop with the profile calculated by solving the Young-Laplace equation. The comparison can be made in several ways; the traditional Bashforth-Adams procedure was used in conjunction with recently calculated drop shape tables which virtually eliminate interpolation errors. Although previous study has found little difference in measurements with pure and oxygen doped silicon, there is other evidence suggesting that oxygen in dilute concentrations severely depresses the surface tension of silicon. The surface tension of liquid silicon in purified argon atmospheres was measured. A temperature coefficient near -0.28 mJ/square meters K was found. The experiments show a high sensitivity of the surface tension to what is believed are low concentrations of oxygen. Thus one cannot rule out some effect of low levels of oxygen in the results. However, the highest surface tension values obtained in conditions which minimized the residual oxygen pressure are in good agreement with a previous measurement in pure hydrogen. Therefore, depression of the surface tension by oxygen is insignificant in these measurements.
Document ID
19860000648
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Hardy, S. C.
(National Bureau of Standards, Washington, DC, United States)
Fine, J.
(National Bureau of Standards, Washington, DC, United States)
Date Acquired
August 12, 2013
Publication Date
May 1, 1985
Publication Information
Publication: NASA, Washington Microgravity Sci. and Appl. Program Tasks
Subject Category
Astronautics (General)
Accession Number
86N10115
Funding Number(s)
CONTRACT_GRANT: NASA ORDER H-27954-B
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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