CHARACTERISTIC TIMES OF OXYGEN MASS-TRANSFER AT THE LIQUID-METAL VAPOR INTERFACE

Citation
E. Ricci et al., CHARACTERISTIC TIMES OF OXYGEN MASS-TRANSFER AT THE LIQUID-METAL VAPOR INTERFACE, Journal of Materials Science, 33(2), 1998, pp. 305-312
Citations number
11
Categorie Soggetti
Material Science
ISSN journal
00222461
Volume
33
Issue
2
Year of publication
1998
Pages
305 - 312
Database
ISI
SICI code
0022-2461(1998)33:2<305:CTOOMA>2.0.ZU;2-V
Abstract
The interactions of liquid metals and alloys with the environment most ly depends on the thermodynamic properties of the liquid surface. In f act, the surface tension is strongly influenced by the presence in the surrounding atmosphere of reactive gases through solution, adsorption mechanisms and/or surface reactions. In particular, oxygen, which sho ws a high surface activity towards a large number of metallic systems, is the most important contaminant of liquid metals and alloys. Theore tical approaches for estimating the oxygen mass transfer at the liquid -vapour interface under inert atmosphere and vacuum have been develope d already in order to relate the observed physical properties to the r eal surface composition data. In the present work a model of the inter facial transport of a liquid metal-oxygen system under Knudsen conditi ons that foresees the temporal evolution of the interfacial compositio n is presented. The diffusion characteristic times for reaching steady -state conditions are evaluated in order to define two system ''sizes' ' depending on the different oxygen transport mechanisms in the liquid phase. An experimental study of the interface evolution is at present under way and preliminary results show a satisfactory agreement with theoretical studies.