Premium
High‐temperature oxidation of industrial FeCrMo steel
Author(s) -
Greeff A. P.,
Louw C. W.,
Swart H. C.
Publication year - 2000
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/1096-9918(200008)30:1<120::aid-sia778>3.0.co;2-i
Subject(s) - oxide , corrosion , metallurgy , materials science , alloy , auger electron spectroscopy , high temperature corrosion , layer (electronics) , oxygen , chromium , iron oxide , atmospheric temperature range , chemical engineering , chemistry , composite material , physics , organic chemistry , meteorology , nuclear physics , engineering
The oxidation resistance of Fe‐based alloys depends on thin protective films consisting of the reaction products between the alloy and the atmosphere. An Fe–9Cr–1Mo steel is used as a corrosion‐resistant alloy in pressurized water reactors in power generation facilities. The high steam temperature and pressure inside the vessel lead to wall thinning in certain areas of the pipe due to erosion corrosion. The pipe's hardness and resistance to corrosion are determined by the composition of the oxide layer. In this study the samples were taken from pieces of pipe removed after failure that which have an operation history of about 20 years. Auger electron spectroscopy was used to measure the segregation and also the influence of oxygen pressure on the oxidation process at 1 × 10 −7 and 5 × 10 −8 Torr over a wide temperature range. Owing to site competition between the sulphur and oxygen atoms, the influence of sulphur segregation is more profound at lower oxygen pressures. According to XPS depth profiles, the oxide layer formed at elevated temperatures has a duplex structure consisting of iron and chromium oxides. Iron oxide is present at the gas/oxide interface, whereas chromium oxide is closest to the oxide/metal interface, with concentrations that depend on the oxidation temperature: below 400 °C the oxide layer consists of Fe 2 O 3 and a small amount of Cr 2 O 3 ; between 400 and 600 °C the oxide layer consists of a mixture of Fe 2 O 3 and Cr 2 O 3 ; and above 600 °C the layer consists mainly of Cr 2 O 3 . Copyright © 2000 John Wiley & Sons, Ltd.