Potentiostatic Study on the Anodic Behaviour of Iron-Nickel Alloys

The anodic behaviour of annealed iron-nickel alloys containing 0 to 100% Ni in deaerated 1 M/L sulphuric acid solutions was studied. A semi-conductor type potentiostat was used for polarization measurements. The results obtained were compared with those for iron-chromium alloys as follows: (1) A negative loop observed in iron-chromium alloys was not shown in the anodic polarization curves of any of the iron-nickel alloys studied. (2) The anodic current densities at the passive state of the iron-nickel alloys were far greater than those of the iron-chromium alloys, but smaller than those of the latter in the trans-passive region. (3) A different Flade potential was obtained for a different setting potential for the alloys containing more than 30% Ni. This phenomenon was not observed in the iron-chromium alloys.