Electrochemical preparation of the Fe-Ni36 Invar alloy from a mixed oxides precursor in molten carbonates

The Fe-Ni36 alloy was prepared via the one-step electrolysis of a mixed oxides precursor in a molten Na2CO3-K2CO3 eutectic melt at 750℃,where porous Fe_(2)O_(3)-NiO pellets served as the cathode and the Ni10 Cu11 Fe alloy was an inert anode.During the electrolysis,Ni O was preferentially electro-reduced to Ni,then Fe_(2)O_(3)was reduced and simultaneously alloyed with nickel to form the Fe-Ni36 alloy.Different cell voltages were applied to optimize the electrolytic conditions,and a relatively low energy consumption of 2.48 k W·h·kg^(-1) for production of Fe Ni36 alloy was achieved under 1.9 V with a high current efficiency of 94.6%.The particle size of the alloy was found to be much smaller than that of the individual metal.This process provides a low-carbon technology for preparing the Fe-Ni36 alloy via molten carbonates electrolysis.