Effects of Ce, Mo and Si ion implantation on the passive layer composition and high-temperature oxidation behaviour of AISI 304 stainless-steel studied by soft x-ray absorption spectroscopy

A. Gutiérrez 1 *, M. F. López 2, F. J. Pérez Trujillo 3, M. P. Hierro 3, F. Pedraza 3

1Departamento de Ciencia y Tecnología de Materiales, Universidad Miguel Hernández, Avda Ferrocarril s/n, E-03202 Elche, Spain

2Ingenería de Materiales, Degradación y Durabilidad, Centro Nacional de Investigaciones Metalúrgicas, Avda. Gregorio del Amo 8, E-28040 Madrid, Spain

3Departamento de Ciencia de Materiales, Universidad Complutense de Madrid, Spain

email: A. Gutiérrez (ale@umh.es)

*Correspondence to A. Gutiérrez, Departamento de Ciencia y Tecnología de Materiales, Universidad Miguel Hernández, Avda Ferrocarril s/n, E-03202 Elche, Spain

Keywords

x-ray absorption spectroscopy; stainless-steel; ionic implantation; high-temperature oxidation; corrosion resistance

Abstract

The influence of Ce, Mo and Si ion implantation on the chemical properties of AISI 304 stainless-steel passive and oxide layers was studied by means of soft x-ray absorption spectroscopy (XAS). Applying this technique at the transition metal 2p absorption thresholds, the composition and chemical state of the passive layer were determined. A surface Cr enrichment is observed for the ion-implanted samples in comparison with non-implanted samples, which can be associated with better corrosion behaviour. To investigate the effects of ion implantation on the high-temperature oxidation behaviour of AISI 304 stainless-steel, the oxide layer formed after an isothermal oxidation at 1173 K for 32 h was also investigated. The XAS data show mainly the presence of Cr and Mn oxides in the surface region of all samples. The Cr/Fe ratio - a parameter that can be associated with the protective character of the oxide scale - is higher for the Si- and Ce-implanted samples than for the as-received sample. The Mo-implanted sample has the lowest Cr/Fe ratio, suggesting a poor oxidation resistance at high temperatures in this case. Copyright © 2000 John Wiley & Sons, Ltd.