chemisorbed oxygen atom at the surface of the embryo on Homogeneous CO gas bubble formation in Fe-C-O melts has the bubble nucleation process. He has suggested that the been studied by assuming that the bubble formation is initiated electrostatic energy due to the interaction between adsorbed by the clustering process of CO molecules formed by the reaction oxygen ions at the embryo surface contributes to reduce the of chemisorbed oxygen at the surface of the cluster with carbon interfacial tension which should be overcome for the bubble atoms impinging on the surface. The electrostatic energy due to formation. However, a reduction in the surface tension value dipole-dipole interaction between the chemisorbed oxygen atoms to 1000 dyne/cm, which is observed on a planar surface at the surface layer of the cluster was included in the free energy when the surface active elements such as oxygen are present for the bubble formation in a melt system characterized with high (7), does lower the supersaturation to 29,000 atm, but still surface tension and low vapor pressure. The calculated values of leaves it at a very high value.
supersaturation for bubble formation, which turn out to be crucially dependent on the oxygen activity, provide the upper bound
A gas bubble nucleation model based on molecular intervalues of the supersaturation for the CO bubble formation in an actions in gas-liquid solutions was proposed by Kwak and iron melt. ᭧ 1998 Academic Press Panton (8). The essence of this model is that the bubble formation in solution is initiated by the clustering process of activated molecules in a metastable state; if any cluster II. MODEL OF CLUSTERING PROCESS OF CO Levine (5, 6) recognized the importance of the effect of
MOLECULES IN Fe-C-O MELTS
In an Fe-C-O melt which is in equilibrium with the gas 1 To whom correspondence should be addressed. pressure, the CO molecules are dissolved as their atomic 113