High Temperature Oxidation of the Austenitic (35Fe27Cr31Ni) Alloy Sanicro 28 in O-2 + H2O Environment
Journal article, 2010

The present study investigates the high temperature oxidation of alloy Sanicro 28 (35Fe27Cr31Ni) in 5% O-2 and in 5% O-2 + 40% H2O. Polished steel coupons were isothermally exposed in a tube furnace at 600, 700 and 800 A degrees C for up to 168 h. The samples were investigated by gravimetry, grazing angle X-ray diffraction (XRD), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy/energy dispersive X-rays (STEM/EDX). The results show that the material forms a protective scale in both environments. The scale is duplex. The inner part of the scale consists of corundum type chromium-rich (Cr (x) Fe1-x )(2)O-3, and the outer layer consists of spinel type oxide. Chromia is lost from the protective oxide by vaporization of CrO2(OH)(2) in O-2 + H2O environment. The capacity of Sanicro 28 to suffer chromia vaporization without forming a rapidly growing iron-rich oxide is attributed to its high Cr/Fe ratio. The spinel formed at the oxide/gas interface could in addition be beneficial for oxidation behavior in wet oxygen because it may slow down chromia evaporation.

Water vapor

stainless-steel

evaporation

oxides

Evaporation

Sanicro 28

304l

flow-rate

chromium

water-vapor

oxygen

900-degrees-c

Oxidation

Author

Carolina Pettersson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Torbjörn Jonsson

Chalmers, Applied Physics, Microscopy and Microanalysis

Christian Proff

Chalmers, Applied Physics, Microscopy and Microanalysis

Mats Halvarsson

Chalmers, Applied Physics, Microscopy and Microanalysis

Jan-Erik Svensson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Lars-Gunnar Johansson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Oxidation of Metals

0030-770X (ISSN) 1573-4889 (eISSN)

Vol. 74 1-2 93-111

Subject Categories

Chemical Sciences

DOI

10.1007/s11085-010-9199-1

More information

Created

10/7/2017