Author/Editor		Milošev, Ingrid; Strehblow, Hans-Henning
Title		The behavior of stainless steels in physiological solution containing complexing agent studied by X-ray photoelectron spectroscopy
Type		članek
Source		J Biomed Mater Res
Vol. and No.		Letnik 52
Publication year		2000
Volume		str. 404-12
Language		eng
Abstract		The passive film formed by electrochemical oxidation on two different stainless steels differing in molybdenum (Mo) content in physiological solution with and without the addition of complexing agent, i.e., citrate, was studied using X-ray photoelectron spectroscopy. The alloys were polarized at different oxidation potentials in the electrochemical chamber attached to the spectrometer. Thus, the composition of the film formed by oxidation was analyzed by X-ray photoelectron spectroscopy without prior exposure to air (quasi in situ). The passive film formed in physialogical solution consists of two predominant oxides, i.e., chromium and iron oxides. Oxides of alloying elements nickel and Mo are also detected in the film. It seems that the strong enrichment of oxidized chromium and Mo in the passive layer, and strong enrichment of Mo and depletion of iron at the metal surface underneath the passive layer, are responsible for the outstanding corrosion resistance of orthopedic stainless steel in physiological solution. Commercial AISI 304 is not suitable for orthopedic applications. The addition of complexing-agent affects significantly the passivation behavior of orthopedic stainless steel, because it changes the distribution of the elements within the passive layer and at the metal surface underneath.
Descriptors		STAINLESS STEEL MOLYBDENUM SURFACE PROPERTIES CORROSION CITRATES SPECTRUM ANALYSIS X-RAYS CHROMIUM IRON IMPLANTS, ARTIFICIAL