Activity Measurements of Mn–In Alloys by the EMF Method with CaF₂ Solid Electrolyte

Abstract

E.M.F. of galvanic cells with the solid electrolyte CaF₂ was measured to determine the activity of manganese in the whole composition range for Mn–In alloys in the temperature range 800 to 1100 K. The cell used was as follows:
(−)Mn, MnF₂|CaF₂(single crystal)|Mn–In, MnF₂(+)
Activity of manganese shows large positive deviation from Raoult’s law, and changes largely in the In-rich liquid phase region, but changes a little in the intermetallic compound Mn₃In region.
The liquidus line derived from emf measurement in this study agrees well with the phase diagram by Hansen and Anderko.