Cobalt cementation with ferromanganese

The thermochemical properties, electrochemical behavior, and potential use for cementation have been investigated for two ferromanganese alloys, standard ferromanganese (6.8% carbon) and medium carbon ferromanganese (1.4% carbon). Standard potentials are obtained by measuring the potential of the galvanic cell consisting of a ferromanganese sample and a saturated mercury-sulfate reference electrode and extrapolating to infinite dilution. Cementation of cobalt on ferromanganese has also been investigated. The rate is measured by rotating-disk experiments and the results show that cobalt cementation on ferromanganese is a firstorder reaction controlled by mass transfer. Tests of cobalt cementation on the ferromanganese (1.4% C) powder are carried out at room temperature. The reaction is fast in the pure sulfate solution and the efficiency of use of manganese is close to 100%. Cementation of cobalt with ferromanganese does not proceed to a significant level in mixed cobalt and zinc-sulfate solution.