Effects Of Buffer Capacity On The Metastable Pitting Behavior Of Stainless Steel

To investigate the pitting and metastable pitting rules of type 304 stainless steel, potentiodynamic polarization method was employed to study the behavior of metastable pitting and stable pitting on 304 stainless steel in sodium bromide solution and borate/phosphate buffered bromide solutions. The influence of the concentration of Br-,the pH value,the buffer capacity and general environmental factor to pitting potential and metastable pitting was studied as well.The environmental factors influenced the behavior of metastable pitting and stable pitting, of which the concentration of Br- and the general environmental factor had the remarkable effect. As the concentration of Br- is lower, the borate and phosphate made the number of metastable pits less, the value of peak current decreased and the lifetime of metastable pits longer. Compared with phosphate, the effect of borate to the metastable pitting is more evident.