  Austenitic Fe-30Mn-1C (FeMnC) is a prospective biodegradable implant material
combining high mechanical integrity with adequate corrosion rates. The fast
solidified TWIP alloy, its constituents and 316L stainless steel were
electrochemically analysed in various electrolytes at 37 {\deg}C under laminar
flow. Potentiodynamic polarization tests were conducted in Trisbuffered
simulated body fluid (SBF), in Tris-buffered saline (TBS) and in 150 mM - 0.15
mM NaCl solutions (pH 7.6, 10, 5, 2) to study initial corrosion stages. Active
dissolution of FeMnC is revealed in all electrolytes and is discussed on basis
of the Fe and Mn behaviour plus is compared to that of 316L. The role of Tris
(Tris(hydroxymethyl)aminomethane) as organic buffer for SBFs is critically
assessed, particularly with view to the sensitivity of Fe. SEM studies of FeMnC
corroded in NaCl revealed preferential dissolution along Mn-rich grain boundary
regions. Static immersion tests of FeMnC in SBF with surface and solution
analyses (SEM/EDX, XPS, ICP-OES) indicated that dissolution processes interfere
with the formation of permeable surface coatings comprising hydroxides and
salts.
