ON THE ACTIVITIES OF Cr AND C IN MOLTEN Fe-Cr-C ALLOYS
Constructing the following electrode concentuation cell, the author measured the electromotive force corresponding to the Change in Cr and C in Fe-Cr-C alloys at about 1, 540°C:
From the following equation the activity of Cr in this alloys was determined for the range of Cr<30% and O<C<Sat.
Fe-Cr binary alloys obey the Raoult's law but Fe-Cr-C alloys show a gradually negative deviation from the Raoult's law on addition of C. and the effect of C on the activity coefficient of Cr was discussed using interaction parameter rccr. In addition, the effect of Cr on the activity coefficient of C was also discussed. Furthermore, behavior of Cr-oxide in molten slag was considered from oxygen potential that controls the system. And the decarburization limit in Fe-Cr-C alloys was calculated from the experimental results.