Self-Activation Behavior of 304 Stainless Steel in Sulfuric acid solution

초록

The stability of the passive film on 304 stainless steel surface was investigated in a sulfuric acid solution. The potential variation with time was measured during the passive-active transition in the open circuit state. Self-activation time, to increased with increasing pH, the passivation time and passivation potential. In the galvanostatic cathodic reduction test, the external current densities, ie within 200nA/cm2 were applied to the passive film during the dissolution of the film. Under various conditions, two kinetic parameters, the amount of the charge accumulated in the film, qo, and the rate of the self-activation process, io were obtained from the linear relationship between density of the applied current and the inverse value of the activation time. These two parameters can be available of evaluating the stability of the passive film. From this results it is confirmed that io represents the dissolution rate of the passive film and qo represents the thickness and quantity of the passive film.