Measurement of Activities in Liquid Fe-Cu, Fe-Cr and Fe-Sn Alloys by a Transportation Method

Abstract

The activities in Liquid Fe-Cu, Fe-Cr and Fe-Sn alloys have been determined by a modified transportation method at 1873 K. The activity coefficients can be calculated by a graphical integration of the following equation using the concentration ratios of the components in vapor and metal phases:(This article is not displayable. Please see full text pdf.) \ oindentwhere Ni and Xi are the mole fraction of the component i in the metal and vapor phases, respectively.In the Fe-Cu system, the activities of iron and copper were found to be largely positive deviations from Raoult’s law over the entire composition range, and the activity coefficients of iron and copper at 1873 K are expressed by the following equations, respectively:(This article is not displayable. Please see full text pdf.) In the Fe-Cr system, the activities of iron show slightly negative deviations from Raoult’s law, with nearly ideal behavior, and the other component, chromium, shows negative behavior and that approximately obeys Henry’s law in the experimental composition range, NCr=0.079−0.508. The activity coefficients of iron and chromium at 1873 K are expressed by the following equations, respectively:(This article is not displayable. Please see full text pdf.) In the investigation of Fe-Sn system, the miscibility limit at 1873 K was determined from the phase diagram of Hansen. Activities of both iron and tin show largely positive deviations from Raoult’s law over the entire composition range.