The electrochemical impedance of polarized 316L stainless steel: structure-property-adsorption correlation.
Electrochemical (EC) impedance and polarization data were synergistically coupled with AFM micrographs providing insight on the polarized alloy-electrolyte interface. Several regions of oxide topography/ impedance characteristic were apparent on a 316L SS surface. A relatively rough surface with apparent EC reaction products was observed below -500 mV. Smooth surfaces were seen from -500 mV to 200 mV. A transition region which displayed the aggregation of particles on the surface was seen from 200 mV to 600 mV. Above 600 mV these particles disappeared revealing a smooth topography. These topographical observations matched closely with the impedance behavior of the system, particularly the capacitance (C), polarization resistance (R(p)) and current density. The presence of pre-adsorbed Fb had a significant impact on C below approximately -500 mV (increased capacitance). The deviation from ideality of the current response as determined by a KWW empirical dielectric decay function showed significant differences between PBS-immersed and pre-adsorbed Fb cases. Earlier, changes in Fb area coverage, height, and eccentricity were observed between voltages lower and higher than 0 mV. The presence of the flat-band potential around -150 mV as well as high cathodic charge-transfer reactions taking place below -100 mV relate to these observations.
Gettens
Robert T T
RT
Department of Biomedical Engineering, Western New England College, Springfield, Massachusetts 01106, USA.
Gilbert
Jeremy L
JL
D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D012996:Solutions; D013193:Stainless Steel / Q000737:chemistry*; D013499:Surface Properties
D001672:Biocompatible Materials; D012996:Solutions; D013193:Stainless Steel