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@PHDTHESIS{Ehlers:24991,
author = {Ehlers, Rolf Jörg and Quadakkers, Willem J.},
title = {{O}xidation von ferritischen 9 - 12 $\%$ {C}r-{S}tählen in
wasserdampfhaltigen {A}tmosphären bei 550 bis 650 {G}rad
{C}elsius},
volume = {3883},
issn = {0944-2952},
school = {Techn. Hochsch. Aachen},
type = {Dr. (FH)},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH, Zentralbibliothek, Verlag},
reportid = {PreJuSER-24991, Juel-3883},
series = {Berichte des Forschungszentrums Jülich},
pages = {III, 199 p.},
year = {2001},
note = {Record converted from VDB: 12.11.2012; Aachen, Techn.
Hochsch., Diss., 2001},
abstract = {Economical and ecological considerations with respect to
the need for reduction of CO$_{2}$ emission and fuel
consumption in conventional steam power plants are leading
to the requirement for the utilities to increase the thermal
efficiency of power generation plant. An increase in steam
temperature from former 535 to 650°C and in steam pressure
from 185 to 300 bar would enable a reduction in fuel
consumption and a reduction of CO$_{2}$ emission of more
than 25\%. A number of high strength 9-12\% Cr steels have
been developed for applications as construction materials in
such advanced power plants. Besides mechanical properties,
the oxidation resistance of these new steels is becoming an
increasingly important material selection criterion. Whereas
exposure tests in oxygen and in air show that the steels
possess excellent oxidation resistance, it is well known
that the presence of water vapour in the test atmosphere
significantly enhances the oxidation rates of these steels.
In the present work, the oxidation behaviour of several of
the new 9-12 wt.\% Cr steels in environments containing
water vapour, mainly Ar-50 vol.\% H$_{2}$O has been studied
especially at temperatures between 550 and 650°C. The
oxidation behaviour is compared to that of common alloys
such as 1CrMoV, 12Cr1MoV and the austenitic steel 316LN.
Besides this, a number of model alloys were investigated to
study the influence of alloying elements on the oxidation
behaviour. A variety of analytical methods have been used,
such as optical microscopy, electron microscopy (SEM incl.
EDX and WDX), transmission electron microscopy (TEM), X-ray
diffraction (XRD), secondary ion mass spectroscopy (SIMS)
and various specially designed experimental techniques, e.
g. in-situ gas change between wet and dry gas, as well as
oxygen-18 isotope tracer experiments. The results of the
oxidation tests clearly indicate that the oxygen coming from
the water vapour is incorporated in the oxide scale in a
different way as the oxygen originating from the O$_{2}$
molecule. A typical feature of 9-12\% Cr-steels is the
bell-shaped temperature dependence of the oxidation rates in
water vapour, i. e. at 550 and especially at 800°C the
oxidation rates are much lower than at 600 to 650°C. For
the enhanced oxidation rates of the 9-12 chromium steels in
environments containing water vapour a mechanism is proposed
which involves the evaporation of volatile iron hydroxide.
Tests with simple model steels have shown that additions of
cobalt may provide significant improvement in the steam
oxidation behaviour of the studied steels.},
cin = {IWV-2},
cid = {I:(DE-Juel1)VDB2},
pnm = {Werkstoff- und Bauteilentwicklung für fortschrittliche
Kraftwerke},
pid = {G:(DE-Juel1)FUEK24},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
url = {https://juser.fz-juelich.de/record/24991},
}