CORROSION RESISTANCE OF 2205 DUPLEX STAINLESS STEEL IN NORMAL SALINE SOLUTION UNDER SIMULATED INFLAMMATORY CONDITIONS

Abstract

ABSTRACT

Different grades of austenitic stainless steels such as 316L, 316LMV, and nickel free-high nitrogen austenitic stainless steels have been introduced for biomedical applications, owing to their biocompatibility, suitable mechanical properties and corrosion resistance. When tested in solutions containing hydrogen peroxide to simulate inflammatory conditions, austenitic stainless steels showed decrease in corrosion resistance.

In this study, 2205 duplex stainless steel was introduced as an alternative candidate for austenitic stainless steel for biomedical applications. The corrosion behavior of 2205 duplex stainless steel was investigated in normal saline solution. The effects of addition of hydrogen peroxide, a reactive oxygen species, simulating an inflammatory condition, and addition of human albumin, a protein found in the biological environment, were simulated.

The corrosion behavior was studied by potentiodynamic polarization and electrochemical impedance spectroscopy.  It was found that the corrosion rate of the 2205 duplex stainless steel significantly decreased in the presence of hydrogen peroxide, while the addition of human albumin did not significantly alter the corrosion resistance of the alloy.

Electrochemical impedance spectroscopy tests showed the increase in the thickness of the passive film of the steel as a result of addition of hydrogen peroxide. Potentiodynamic polarization experiments showed that hydrogen peroxide, and to a lower extent, human albumin served as an anodic inhibitor as indicated by the shift of corrosion potential towards more positive values and the corrosion current density towards lower values.