Towards understanding Shewanella algae-induced degradation of passive film of stainless steel based on electrochemical, XPS and multi-mode AFM analyses

The degradation of the passive film of stainless steel caused by Shewanella algae was investigated through electrochemical tests, X-ray photoelectron spectroscopy and atomic force microscopy (AFM). The dynamic mode and the nano manipulation mode of AFM were adopted to obtain the 3D topography of cell/passive film interfaces and to manipulate cell movement, respectively. The surface Volta potential scanning by tapping-amplitude modulation mode and the conductivity tests by PeakForce-TUNA mode of AFM revealed the electron injection phenomenon from S. algae cells into adjacent passive film, which promoted the reduction of Fe3+ compounds and accelerated the degradation of passive film.