A modified closed chamber method has been applied to determine the effect of the alloying element on the activity coefficient of manganese in liquid iron alloy. The results obtained are summarised as follows:
(1) Interaction parameter
eMn(X) in liquid iron alloy at 1570°C:
The value of
eMn(C) is in fairly good agreement with those of previous investigators obtained by a different method.
(2) Enthalpy coefficient
hMn(X) and entropy coefficient
sMn(X) defined by Chipman et al. are obtained for X=C and Si as follows:
(3) In consideration of the large discrepancy in
eMn(SI)'s of the present authors and previous investigators, it is shown that H
2-H
2O method has a possibility of making considerable errors by the effects of hydrogen, oxygen, and SiO in determination of
eO(O),
eSI(SI), and
eO(SI), which were used to obtain
eSI(Mn) by the previous investigators.
(4) A regular periodic relation is found between the interaction parameter ε
Mn(X) and atomic number of the alloying element X.
(5) The interaction parameter ε
eMn(X) shows a tendency to decrease with increasing the effective number of free electron
nx, eff of the alloying element X.
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