Surface Tension, Interfacial Segregation, and Graphite Shape in Cast Irons

Abstract

Using literature data on iron melts, an expression of the surface tension of cast iron melts as a function of temperature and composition was obtained. Its predictions were satisfactorily compared with reported experimental results. Then, an analysis of experimental information of sessile drop experiments with cast iron melts onto graphite substrates showed a strong adhesion between these two phases when sulfur is present and its dramatic decrease when the sulfur activity is reduced by the addition of spheroidizers such as Mg and Ce. Finally, analysis and discussion of results on the segregation of impurities and trace elements at the graphite matrix interface in cast irons led to the proposal of a scheme for their effect on graphite shape.