The corrosion behavior of 9Cr ferritic–martensitic heat-resistant steel was investigated in water and chloride environment at room temperature (RT). The results of linear polarization, electrochemical impedance spectroscopy (EIS), and potentiodynamics (PD) polarization tests on long-term exposure show that 9Cr ferritic–martensitic steel has weaker corrosion resistance and greater pitting corrosion tendency in higher chloride concentrations. Corresponding scanning electron microscopy (SEM) observation displays that higher concentration chloride promotes the pitting initiation. During long-term exposure, pitting susceptibility decreases, the average pit size increases, and the density declines in higher chloride concentrations. Pits in the grains and along the grain boundaries are observed by optical microscope (OM), and it indicates that inclusions in grains and carbide particles at grain boundaries are the sites susceptible to pitting initiation.

References

References
1.
Yi
,
Y.
,
Lee
,
B.
,
Kim
,
J.
, and
Jang
,
J.
,
2006
, “
Corrosion and Corrosion Fatigue Behaviors of 9Cr Steel in a Supercritical Water Condition
,”
Mater. Sci. Eng., A
,
429
(
1–2
), pp.
161
168
.10.1016/j.msea.2006.05.035
2.
Toloczko
,
M. B.
,
Hamilton
,
M. L.
, and
Maloy
,
S. A.
,
2003
, “
High Temperature Tensile Testing of Modified 9Cr-1Mo After Irradiation With High Energy Protons
,”
J. Nucl. Mater.
,
318
, pp.
200
206
.10.1016/S0022-3115(03)00023-0
3.
Ennis
,
P. J.
, and
Czyrska-Filemonowicz
,
A.
,
2003
, “
Recent Advances in Creep-Resistant Steels for Power Plant Applications
,”
Sadhana
,
28
(
3–4
), pp.
709
730
.10.1007/BF02706455
4.
Výrostková
,
A.
,
Kroupa
,
A.
,
Janovec
,
J.
, and
Svoboda
,
M.
,
1998
, “
Carbide Reactions and Phase Equilibria in Low Alloy Cr–Mo–V Steels Tempered at 773–993 K—Part I: Experimental Measurements
,”
Acta Mater.
,
46
(
1
), pp.
31
38
.10.1016/S1359-6454(97)00238-3
5.
Kim
,
B.-J.
,
Kim
,
H.-J.
, and
Lim
,
B.-S.
,
2008
, “
Creep-Fatigue Damage and Life Prediction in P92 Alloy by Focused Ultrasound Measurements
,”
Met. Mater. Int.
,
14
(
4
), pp.
391
395
.10.3365/met.mat.2008.08.391
6.
Jin
,
S. X.
,
Guo
,
L. P.
,
Li
,
T. C.
,
Chen
,
J. H.
,
Yang
,
Z.
,
Luo
,
F. F.
,
Tang
,
R.
,
Qiao
,
Y. X.
, and
Liu
,
F. H.
,
2012
, “
Microstructural Evolution of P92 Ferritic/Martensitic Steel Under Ar+ Ion Irradiation at Elevated Temperature
,”
Mater. Charact.
,
68
, pp.
63
70
.10.1016/j.matchar.2012.03.009
7.
Xu
,
H.
,
Yuan
,
J.
,
Zhu
,
Z. L.
,
Zhang
,
Q.
, and
Zhang
,
N. Q.
,
2014
, “
Oxidation Behavior of Ferritic-Martensitic Steel P92 Exposed to Supercritical Water at 600 °C/25 MPa
,”
J. Chin. Soc. Corros. Prot.
,
34
(
2
), pp.
119
124
.10.11902/1005.4537.2013.085
8.
Hayakawa
,
M.
,
Hara
,
T.
,
Matsuoka
,
S.
, and
Tsuzaki
,
K.
,
2000
, “
Microstructural Observation of Tempered Martensite in Medium-Carbon Low-Alloy Steel by Atomic Force Microscopy
,”
J. Jpn. Inst. Met.
,
64
(
6
), pp.
460
466
.
9.
Hayakawa
,
M.
,
Matsuoka
,
S.
, and
Tsuzaki
,
K.
,
2001
, “
Observations of Prior Austenite Grain Boundaries and Carbides in the Same Area of Tempered Martensite in Medium-Carbon Steel by Atomic Force Microscopy
,”
J. Jpn. Inst. Met.
,
65
(
8
), pp.
734
741
.
10.
Banas
,
J.
,
Stypula
,
B.
,
Banas
,
K.
,
Swiatowska-Mrowiecka
,
J.
,
Starowicz
,
M.
, and
Lelek-Borkowska
,
U.
,
2009
, “
Corrosion and Passivity of Metals in Methanol Solutions of Electrolytes
,”
J. Solid State Electrochem.
,
13
(
11
), pp.
1669
1679
.10.1007/s10008-008-0649-5
11.
Cavalcanti
,
E.
,
Wanderley
,
V. G.
,
Miranda
,
T. R. V.
, and
Uller
,
L.
,
1987
, “
The Effect of Water, Sulphate and pH on the Corrosion Behavior of Carbon Steel in Ethanolic Solutions
,”
Electrochim. Acta
,
32
(
6
), pp.
935
937
.10.1016/0013-4686(87)87086-X
12.
Lou
,
X. Y.
, and
Singh
,
P. M.
,
2010
, “
Role of Water, Acetic Acid and Chloride on Corrosion and Pitting Behaviour of Carbon Steel in Fuel-Grade Ethanol
,”
Corros. Sci.
,
52
(
7
), pp.
2303
2315
.10.1016/j.corsci.2010.03.034
13.
Liu
,
F. G.
,
Du
,
M.
,
Zhang
,
J.
, and
Qing
,
M.
,
2008
, “
Inhibition Mechanism of Imidazoline Derivative Inhibitor for Q235 Steel in Saltwater Saturated With CO2
,”
Acta Phys.-Chim. Sin.
,
24
(
1
), pp.
138
142
.
14.
Wang
,
B.
,
Du
,
M.
,
Zhang
,
J.
, and
Gao
,
C. J.
,
2011
, “
Electrochemical and Surface Analysis Studies on Corrosion Inhibition of Q235 Steel by Imidazoline Derivative Against CO2 Corrosion
,”
Corros. Sci.
,
53
(
1
), pp.
353
361
.10.1016/j.corsci.2010.09.042
15.
Luo
,
H.
,
Dong
,
C. F.
,
Li
,
X. G.
, and
Xiao
,
K.
,
2012
, “
The Electrochemical Behaviour of 2205 Duplex Stainless Steel in Alkaline Solutions With Different pH in the Presence of Chloride
,”
Electrochim. Acta
,
64
, pp.
211
220
.10.1016/j.electacta.2012.01.025
16.
Raistrick
,
I. D.
,
Franceschetti
,
D. R.
, and
MacDonald
,
J. R.
,
2005
, “
Theory
,”
Impedance Spectroscopy: Theory, Experiment, and Application
,
2nd ed.
,
E.
Barsoukov
, and
J. R.
MacDonald
eds.,
Wiley
,
Hoboken, NJ
, Chap. 2.
17.
Kosec
,
T.
,
Merl
,
D. K.
, and
Milošev
,
I.
,
2008
, “
Impedance and XPS Study of Benzotriazole Films Formed on Copper, Copper–Zinc Alloys and Zinc in Chloride Solution
,”
Corros. Sci.
,
50
(
7
), pp.
1978
1997
.10.1016/j.corsci.2008.04.016
18.
Macdonald
,
D. D.
,
1992
, “
Point Defect Model for the Passive State
,”
J. Electrochem. Soc.
,
139
(
12
), pp.
3434
3449
.10.1149/1.2069096
19.
Kocijan
,
A.
,
Merl
,
D. K.
, and
Jenko
,
M.
,
2011
, “
The Corrosion Behavior of Austenitic and Duplex Stainless Steels in Artificial Saliva With the Addition of Fluoride
,”
Corros. Sci.
,
53
(
2
), pp.
776
783
.10.1016/j.corsci.2010.11.010
20.
Wang
,
B.
,
Zhang
,
L. W.
,
Su
,
Y.
,
Xiao
,
Y.
, and
Liu
,
J.
,
2013
, “
Corrosion Behavior of 5A05 Aluminum Alloy in NaCl Solution
,”
Acta Metall. Sin.
,
26
(
5
), pp.
581
587
.10.1007/s40195-013-0018-y
21.
Zheng
,
S.
,
Li
,
C.
,
Qi
,
Y.
,
Chen
,
L.
, and
Chen
,
C.
,
2013
, “
Mechanism of (Mg,Al,Ca)-Oxide Inclusion-Induced Pitting Corrosion in 316L Stainless Steel Exposed to Sulphur Environments Containing Chloride Ion
,”
Corros. Sci.
,
67
, pp.
20
31
.10.1016/j.corsci.2012.09.044
22.
Zhang
,
C. Y.
,
Chen
,
X. Q.
,
Chen
,
D. B.
,
Li
,
G. M.
, and
Pan
,
R. Y.
,
2001
, “
Research of Pitting Susceptibility in Low Carbon Steels and Mechanism of Pitting Initiation
,”
J. Chin. Soc. Corros. Prot.
,
10
(
5
), pp.
265
272
.10.3969/j.issn.1005-4537.2001.05.002
23.
Chiba
,
A.
,
Muto
,
I.
,
Sugawara
,
Y.
, and
Hara
,
N.
,
2013
, “
Pit Initiation Mechanism at MnS Inclusions in Stainless Steel: Synergistic Effect of Elemental Sulfur and Chloride Ions
,”
J. Electrochem. Soc.
,
160
(
10
), pp.
511
520
.10.1149/2.081310jes
24.
Shashank Dutt
,
B.
,
Nani Babu
,
M.
,
Shanthi
,
G.
,
Venugopal
,
S.
,
Sasikala
,
G.
, and
Bhaduri
,
A. K.
,
2012
, “
Influence of Microstructural Inhomogeneities on the Fracture Toughness of Modified 9Cr-1Mo Steel at 298-823 K
,”
J. Nucl. Mater.
,
421
(
1–3
), pp.
15
21
.10.1016/j.jnucmat.2011.11.035
25.
Zhang
,
B. H.
,
2005
,
Electrochemical Corrosion and Protection of Metal
,
Higher Education Press
,
Beijing
, p.
84
.
26.
Sikka
,
V. K.
,
Ward
,
C. T.
, and
Thomas
,
K. C.
,
1983
, “
Modified 9Cr-1Mo Steel—An Improved Steel for Steam Generator Application
,”
Ferritic Steels for High Temperature Applications: Proceedings of ASM International Conference on Production, Fabrication, Properties and Application of Ferritic Steels for High Temperature Applications, Warren, PA, 6–8 October 1981
,
A. K.
Khare
, ed.,
ASM
,
Metals Park, OH
, pp.
65
84
.
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