Abstract: The solubility of C in Mn melt at different contents of Si at 1350℃ was determined.The sol- ubility of Ca in Mn melts containing C in CaC_2 crucible under sealed condition at 1350℃ was ascertained.With these data,evaluation of the activity interaction coefficients e_C~(Si),e_C~C, e_C~(Ca) as well as γ_C~0 was made.The standard free energy of solution of C in liquid Mn based on the 1 wt-% solution standard,formulated in relation to T,was also estimated.Brief dis- cussion was made as to the confiormability of results with those given in the literature.

Key words: thermodynamics, activity interaction coefficients, Mn, C, Ca, Si