Author/Editor		Slemnik, Mojca; Milošev, Ingrid
Title		An impedance study of two types of stainless steel in Ringer physiological solution containing complexing agents
Type		članek
Source		J Mater Sci-Mater M
Vol. and No.		Letnik 17
Publication year		2006
Volume		str. 911-8
Language		eng
Abstract		The effect of complexing agents EDTA and citric acid on the electrochemical behaviour of AISI 304 and orthopaedic stainless steels in Ringer physiological solution was investigated by potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS). The content of Mo has a pronounced effect on the corrosion resistance, as evident by the broader passive range of the orthopaedic stainless steel containing Mo. The addition of complexing agents induces significant changes in polarization and impedance characteristics, i.e., the shift of corrosion and breakdown potentials in a more negative direction, an increase in current density, and a significant decrease in charge transfer resistance. The results were interpreted by the formation of soluble complexes of metal ions with chelating agents, especially EDTA, which suppressed the formation of the outer Fe(III) layer of the passive film. The impact of complexing agent on the electrochemical parameters was found to be related to its concentration in electrolyte and the stability constant of the complex formed with the related metal ion.
Descriptors		STAINLESS STEEL EDETIC ACID CITRIC ACID CORROSION MOLYBDENUM POTENTIOMETRY SPECTROPHOTOMETRY ELECTRIC IMPEDANCE MATERIALS TESTING