Measurement of anode potentials at high current densities in NaNO sub 3 and NaClO sub 3 media by the current interruption method for metals used in aviation technology

The IR-free anode potential of mild steel, nickel and four Ni-Cr-Fe alloys were studied at high current densities (1-100 A cm exp -2 ) in NaNO sub 3 and NaClO sub 3 solutions. A constant current interruption technique was employed and the flow rate of the electrolytes was 14 m/s (Re=7370). A plot of the anode potential against logarithm of current density yielded a Tafel line over a broad range of current densities. The plateau visible on the anode potential against current density curve was attributed to salt film formation. This explanation was confirmed by visual observation of the anode surface.