De-alloying of 316 stainless steel in the presence of a mixture of metal-oxidizing bacteria

The corrosion behavior of 316 stainless steel was investigated in the presence of a mixture of metal-oxidizing bacteria isolated from marine environments. Ennoblement of stainless steel in the presence of these bacteria can lead to localized corrosion that confirmed by ESEM images. The corrosion rate of the metals also increased. EDS results showed that these bacteria caused the segregation of Si elements in the metal structure and promoted the depletion of Cr and Fe contents in the corrosion products. Thus, the de-alloying of stainless steel can occur in the presence of metal-oxidizing bacteria.

► Metal-oxidizing bacteria were isolated from marine environments.
► Bacteria increased EOCP and corrosion rate of 316 stainless steel.
► Segregation of Si ions from the metal occurred in the presence of bacteria.
► The bacteria depleted the Cr and Fe contents in the corrosion products.
► Pitting and de-alloying of 316 stainless steel occurred.