Electrochemical and SEM study on Type 254 SMO stainless steel in chloride solutions

www.elsevier.com/locate/corsci

Corrosion Science 46 (2004) 2431–2444

Electrochemical and SEM study on Type 254SMO stainless steel in chloride solutions

E.A. Abd El Meguid *, A.A. Abd El Latif

Department of Electrochemistry and Corrosion, National Research Centre, Dokki, Cairo, Egypt

Received 30 April 2003; accepted 29 January 2004

Available online 30 April 2004

Abstract

An investigation was conducted to examine the critical crevice potential (Ecrev) and the

critical protection potential (Eprot) for Type 254 SMO stainless steel in 4% NaCl solution by

using potentiodynamic cyclic anodic polarization (PCAP) technique at temperature ranging

from 30 to 90 �C. The critical crevice temperature (CCT) and the critical crevice protection

temperature (Tprot) were determined by plotting the values of breakdown potential and Eprot

versus solution temperature, respectively. The values of CCT and Tprot were recorded at the

abrupt transition with increasing the temperature from transpassive corrosion to crevice

corrosion and were found to be at 55 and 52 �C, respectively. Above CCT (70 �C) the fol-

lowing points were recorded. The Ecrev and Eprot decreased linearly with log [Cl�]. The addition

of bromide ions to chloride ions at a fixed halide content of 4% increased both Ecrev and Eprot.

The Ecrev value in 4% NaCl increased linearly with increasing pH in the range 1–10. The

addition of 0.5 M bicarbonate ions to 4% NaCl completely removed the crevices effect while

increasing the addition of sulphate ions to 4% NaCl increased both of Ecrev and Eprot. The

morphology of the crevice corrosion produced on the steel surface was examined by scanning

electron microscope (SEM) after PCAP treatment under different test conditions.

� 2004 Elsevier Ltd. All rights reserved.

Keywords: Stainless steel; Temperature; Crevice corrosion potential

1. Introduction

Type 254 SMO stainless steel has been recently used in condenser tubes of desali-nation plants instead of copper base alloys because it has better corrosion resistant and

* Corresponding author. Fax: +20-2-337-0931.

E-mail address: [email protected] (E.A. Abd El Meguid).

0010-938X/$ - see front matter � 2004 Elsevier Ltd. All rights reserved.

doi:10.1016/j.corsci.2004.01.022

mail to: [email protected]

2432 E.A. Abd El Meguid, A.A. Abd El Latif / Corrosion Science 46 (2004) 2431–2444

environmentally more friendly [1]. This steel is one of the high strength molybdenum

containing stainless steels which were studied in Arabian Gulf water [2], in reverse

osmosis (RO) and multi-stage flash (MSF) evaporation plants in the Middle East [3]

and in North Sea offshore oil industry [4]. The factors affecting the corrosion properties

of high strength molybdenum containing stainless steels in seawater such as compo-

sition, weldability, biofilm formation, pollution and chlorination are also studied [5,6].The excellent corrosion resistance of a Type 254 SMO stainless steel in chloride solution

is due to the synergistic action of the alloying elements [7]. Therefore, a comparative

study was carried out between the Type 254 SMO and Hastelloy C276 in HCl media [8].

A Type 254 SMO stainless steel was developed by using 6% molybdenum as an alloying

element to stabilize the passive film in chloride-containing media and thus reduce

susceptibility to crevice corrosion. Many models of the chemistry and potential in

crevices have been developed for predicting the initiation and propagation of the cre-

vice attack on stainless steel surfaces [9–13]. The models vary in their range of appli-cability as highlighted by Laycock et al. [14]. There is considerable interest in the

behaviour of crevices formed on the high molybdenum stainless steel due to the increase

in their application in the desalination plant [15] and other industries.

The purpose of the present investigation was to study the CCT and the Tprot in 4%

NaCl. The investigation was also extended to study some environmental factors such

as the influence of chloride ions concentration, pH, addition of bromide ions to

chloride ions at a fixed total halide of 4%, addition of sulphate ions and bicarbonate

ions to 4% NaCl on both Ecrev and Eprot at 70 �C. The surface morphology of thecrevices was examined after PCAP treatment in some of the previous test solutions.

2. Experimental details

The electrodes were cut from 1 mm thick sheet of a UNS S 31254 (254 SMO)

stainless steel supplied by Avesta AB (Sweden), with the following chemical com-

position (W%) 0.017 C, 17.9 Ni, 19.7 Cr, 6 Mo, 0.195 N, 0.7 Cu and balance Fe. A 1

mm thick sheet of 254 SMO was cut into discs of 14 mm in diameter as electrodes for

electrochemical measurements. These electrodes were polished with emery paper down

to 1000 grit. Then they were finely polished with 0.05 lm alumina paste, ultrasonically

cleaned and finally rinsed with double distilled water. The disc electrode to be crevicedwas pressed onto a PTFE disk crevice former at a constant torque of 5 in. lb (0.56

Nm). This torque was found to produce a crevice gap of 4 lm, found by determining

the amount of the solution contained in the crevice when torqued to 5 in. lb given that

diameter of the crevice. The assembly of the creviced disc electrode is shown in Fig. 1.

The assembly of the creviced disc electrode was introduced to a conventional

electrolytic cell of 500 ml contained the test solution. Electrical connection to the

sample was made through an isolated Cu wire. All test solutions were prepared from

analytical grade reagents and double distilled water. The experiments were conductedunder thermostat condition at a desired temperature ranging from 30 to 90 �C.

The electrolytic cell had three openings and was attached to condenser to avoid

evaporation of the electrolyte at elevated temperatures. A saturated calomel electrode

Disc ElectrodeRubber O Ring PTFE

Cu DiscPTFE Cover

Cu Wire

Rubber Cover

Fig. 1. Assembly of the crevice disc electrode.

E.A. Abd El Meguid, A.A. Abd El Latif / Corrosion Science 46 (2004) 2431–2444 2433

(SCE) was used as the reference electrode and all potentials quoted here refer to this

scale. A 10 cm length of 3 mm diameter graphite rod was used as the counter electrode.

The PCAP measurements were carried out for the steel in different solutions by using

a Potentiostat/Galvanostat Model 263A EG & G PARC connected to a fully

compatible IBM computer and controlled by EG & G model 352 CorrosionMeasurement and Analysis Software. PCAP experiments at 5 mV s�1 were utilized

to determine breakdown potential and Eprot at different temperatures. Ecrev was

determined potentiodynamically and reported as the potential at which the current

density continuously exceeds 100 lAcm�2 and Eprot was determined potentiodynam-

ically at the same scan rate as a potential at which the current density goes below 100

lAcm�2 in the reverse scan. At a situation where Eprot was the same as open circuit

potential value on the reverse scan, in such cases Eprot becomes the lowest value

recorded. Three measurements were made for each experimental condition. The valueof 100 lAcm�2 was chosen because it is corresponding to a marked deviation from the

passive current density which was in the range of 5–50 lAcm�2 depending on the

experimental temperature. At the end of each experiment, the sample was examined

microscopically. In most cases, crevice corrosion was successfully observed. The CCT

and the Tprot for crevice were determined at the abrupt transition with increasing the

temperature from transpassive corrosion to crevice corrosion when breakdown

potential and Eprot are plotted versus temperature, respectively. The temperature

figures given here refer to the temperature of the solution.

3. Results and discussion

3.1. Critical crevice and protection crevice potentials

Fig. 2a–c shows the PCAP curves of creviced 254 SMO steel obtained in 4% NaCl

at 32, 55 and 90 �C. The curves generally reveal that as the temperature increased,


the passive current density increased and the breakdown potential decreased, which

made the solution more aggressive. At 32 �C there was a broad passive region with a

passivation current density of 10 lA cm�2 without any sign for localized corrosion

breakdown until the oxygen evolution with a little hysteresis loop on the reverse scan

was observed. This hysteresis loop should be attributed to the dissolution in the

transpassive region [16]. While at 55 �C the PCAP curve (Fig. 2b) indicated thepresence of crevice corrosion breakdown potential at 571 mV which sustained anodic

current density of 100 lA cm�2. On the backward anodic scan a hysteresis loop was

detected. The occurrence of the hysteresis loop is related to the presence of aggressive

solution formed inside the occluded area which maintained when the potential was

reversed. Therefore, it was clear that the increase in the temperature significantly

decreased the breakdown potential. Before crevice corrosion initiation, the aggres-

siveness of the solution inside the crevice was determined by the passive current

density and the geometry of the crevice. The crevice corrosion initiation occurs whenthe solution pH became lower than certain critical pH, thus the current inside the

crevice increased by orders of magnitude, which led to further lowering in the pH as

a result of hydrolysis. The large number of metal ions being dissolved attracted

chloride ions from outside for neutralizing charges. The solution inside the crevice

became saturated with metal chlorides. Precipitation of a very thin salt film occurred

until the metal ion flux across the salt layer was balanced with the diffusion flux out

of the crevice [17]. During the propagation, the solution inside the crevice was a

saturated chloride solution. When the potential was reversed to obtain the protectionpotential value, it was the active corrosion current density and not the passive

current density that determined Eprot. The active corrosion current is a function in

several parameters such as the potential and temperature. At 90 �C the PCAP curve

10-7 10-5 10-3 10-1

-400

-200

0

200

400

600

800

1000

1200

cba

E,m

V SCE

Current Density,(A/cm2)

(a) 32oC (b) 55oC (c) 90 oC

Fig. 2. PCAP curves of creviced sample of Type 254 SMO stainless steel in 4% NaCl with potential scan

rate 5 mV s�1 at (a) 32 �C, (b) 55 �C and (c) 90 �C.


(Fig. 2c) revealed that the experimental condition became suitable for localized

corrosion attack (both of pitting and crevice corrosion); this result is in agreement

with that the CPT for Type 254 SMO was around 90 �C for this alloy in chloride

solution [18,19].

Fig. 3 represents SEM micrographs of a Type 254 SMO steel surface obtained

after PCAP treatment in 4% NaCl at different temperatures. The micrograph of thesurface obtained after PCAP treatment in 4% NaCl at 32 �C shows a passive surface

without any localized attack (Fig. 3a). At 55 �C, an evidence of strong crevice cor-

rosion contains a large number of small pits and a micro-crack was seen at the

boundary between the passive area and the crevice corrosion one, the micro-crack

Fig. 3. Effect of temperature on crevice morphology of Type 254 SMO stainless steel obtained after PCAP

treatment in 4% NaCl at (a) 32 �C, (b) 55 �C and (c) 90 �C. High magnification (c) for pit and crevice are

shown at (d) and (e).


was formed from gathering a large number of small pits (Fig. 3b). With raising the

temperature to 90 �C, an aggressive cracked crevice corrosion with strong pitting

attack on the passive part of the surface were observed (Fig. 3c). The magnification

of the crevice corrosion area and the pitting corrosion formed on the passive part of

the steel surface is shown in Fig. 3d and e, respectively. It was clear that crevice

corrosion area consistent of roughened part which contains a small pits and strongunderneath attack at the boundary with the passive area. This means that crevice

corrosion initiated under the crevice at a critical potential and critical temperature

where the crevice solution can change the metastable pitting to stable ones. The

condition in this work could lead to an aggressive attack approximately similar to

that reported for a Type 254 SMO in seawater using immersion technique [20].

3.2. The critical crevice and protection temperatures

The transition from passive state to crevice corrosion with the increasing in

temperature indicates that the steel resistance to crevice corrosion decreases with

raising the solution temperature. The relationship between both of breakdown po-

tential and Eprot with temperature is utilized for determination of CCT and the

critical protection temperature, respectively, for 254 SMO steel in 4% NaCl solution.

The curves are characterized by S-shape as shown in Fig. 4. It was clear that at acertain temperature there was an abrupt decrease in both breakdown potential and

Eprot. This transition from transpassive dissolution to crevice corrosion is defined as

CCT (temperature below which stable crevice corrosion will not occur at any po-

tential for a given alloy). On the other hand, the transition from the most noble

values of Eprot to an active potential has the same trend as CCT but it is so-called the

critical protection temperature (Tprot) for crevice. Tprot is the temperature below which

30 40 50 60 70 80 90-200

0

200

400

600

800

1000

E,m

V SCE

Temp.oC

ECrev Eprot

Fig. 4. Effect of temperature on Ecrev and Eprot for Type 254 SMO stainless steel in 4% NaCl.


initiation of crevice never occur at any potential for a given metal. The curves of Fig.

4 indicate that the Tprot for Type 254 SMO steel occurs at a little lower temperature

level (52 �C) than CCT (55 �C) in 4% NaCl. This result is very important from

engineering point of view, where it does not possible for the already initiated crevice

corrosion on the steel to propagate at much lower temperature. On contrary, It was

reported [15] that the CCT was 50–60 �C for a cast quality of UNS S31254 steel in3% NaCl and it was possible to maintain active crevice corrosion at a temperature as

low as 10 �C. Laycock et al. [14] reported that if metastable pits initiate crevice

corrosion and the CCT is the lowest temperature at which crevice corrosion occurs,

the CCT should be corresponding to the lowest temperature at which metastable

pitting is possible. This assumes that the crevice corrosion propagation is possible if

metastable pitting is possible, which seems reasonable since crevice can propagate at

relatively low potential as will be discussed later.

3.3. Effect of chloride ions concentration on Ecrev and Eprot

The effect of the chloride ion concentrations on the Ecrev and Eprot after PCAP

treatment were examined at 70 �C. This temperature was selected because it was

sufficiently above the CCT for Type 254 SMO steel in 4% NaCl solution. The results

are represented in Fig. 5. Fig. 5 reveals that both Ecrev and Eprot were linearly de-creased with the logarithm of chloride concentration at 70 �C. The two crevice

potentials were expressed by the conventional form

Fig. 5

E ¼ A� B log½Cl��

where A and B are constants. It was found that B value are 227 and 72 mV/decade for

the variation of Ecrev and Eprot, respectively, with logarithm chloride ion concentra-

tion. The line of Eprot versus the logarithm of chloride concentration is displaced, in

0.1 1-200

0

200

400

600

800

E, m

V SCE

[Cl-] / mol dm-3

ECrev Eprot

. Effect of chloride ion concentrations on Ecrev and Eprot for Type 254 SMO stainless steel at 70 �C.


the negative direction, from that for Ecrev by 690 mV at low concentration and this

value decreased to 475 mV at high concentration. This indicates that the initiated

crevice corrosion on the steel can continue to grow when the potential was reduced

less than those values. It has been reported that the B values for different steels are

dependent on the steel type and the aggressiveness of the environment [21,22].

However, Newman [23] reported that the slope B should be 60 mV for steel inchloride solution at 25 �C. He attributed the higher values of B founded for stainless

steels to the formation of chloro-complexes of chromium.

3.4. Effect of pH on Ecrev and Eprot

Fig. 6 shows the relation between the crevice potentials (Ecrev and Eprot) of Type

254 SMO steel and the pH of 4% NaCl solutions at 70 �C. The Ecrev value decreased

linearly with decreasing pH value with a slope of 37.5/pH unit, whereas the Eprot was

pH independent. This is probably because the low pH aiding localized acidification

[24] which facilitates the crevice initiation. It was observed that crevice corrosion

initiated on the creviced sample of Type 254 SMO steel in 4% NaCl at 90 �C atpotential more active than pitting potential of crevice free samples as shown in Fig.

7. It was also clear from the polarization curves that the passive current density in

case of crevice is higher than the passive current density in case of pitting. However,

the crevice corrosion potential was close to the metastable pitting potential which

was normally more active than the pitting potential for the same metal [14]. This

result was regarded as supporting evidence for the metastable pitting model of

crevice corrosion. Stockert and Boehni [25] proposed that metastable pits could be

stabilized by crevice walls, so that crevice corrosion was simply a geometricallystabilized form of pitting. The aggressiveness nature of the crevice attack decreased

2 4 6 8 100

100

200

300

400

500

600

700

E,m

V SCE

pH

ECrev Eprot

Fig. 6. The relation between Ecrev and Eprot for Type 254 SMO stainless steel and pH of 4% NaCl at 70 �C.

10-8 10-6 10-4 10-2 100

-400

-200

0

200

400

600

800

1000

1200

b

aE,

mV SC

E

Current Density, (A/cm2)

(a): pure Pitting(b): Crevice + pitting

Fig. 7. PCAP curves of Type 254 SMO stainless steel in 4% NaCl with potential scan rate 5 mV s�1 at

90 �C, (a) creviced free sample (b) creviced sample.


with increasing the pH values this could be attributed to the role of OH� ions which

inhibit the localized corrosion [26].

3.5. Effect of bromide ions on crevice potentials and surface morphology

The relation between both of Ecrev and Eprot of Type 254 SMO steel and the

bromide ion to chloride ion ratio, with a fixed halide content of 4% at 70 �C is

represented in Fig. 8. The Ecrev did not change with the variation of bromide to

0.0 0.2 0.4 0.6 0.8 1.0-100

0

100

200

300

400

500

600

E, m

V SCE

[Br- ]/[Br- ]+[Cl- ]

ECrev Eprot

Fig. 8. Effect of of bromide ions to chloride ions ratio at a fixed halide ions concentration of 4% on Ecrev

and Eprot for Type 254 SMO stainless steel at 70 �C.


chloride ratio whereas Eprot increased at high ratio of Br�. Although this relation was

similar to that found for Epit and Eprot of crevice free of Type 254 SMO steel in

similar bromide to chloride ratio at 90 �C [19], it was dissimilar to that reported for

904 L stainless steel [22]. This difference in the trend could be attributed to the

difference in composition of high molybdenum containing stainless steels. SEM

micrographs of crevice corrosion formed on Type 254 SMO steel in the presence ofvarious ratios of chloride and bromide with a fixed halide content of 4% at 70 �Cafter PCAP treatment are represented in Fig. 9. The presence of 25% Br� from the

Fig. 9. SEM micrographs of the creviced sample of Type 254 SMO surface after PCAP treatment in

different bromide ions to chloride ions ratio at a fixed halide ions concentration of 4% at 70 �C (a) 75%

NaCl+ 25% NaBr (b) 50% NaCl+ 50% NaBr (c) pit formed on crevice free part in the case of (b).


total halide content led to a deep crack in the crevice corrosion area (Fig. 9a). This

crack grows in depth and width with increasing the bromide ratio to 50% beside the

appearance of lace like pit in crevice free part of the electrode as shown in Fig. 9b

and c, respectively.

3.6. Effect of the addition of sulphate and bicarbonate ions on crevice corrosion

To examine the possibility of crevice corrosion inhibition by other anions, dif-

ferent concentrations of SO2�4 and HCO�

3 were added to 4% NaCl at 70 �C. Figs. 10and 11 represent the PCAP curves of Type 254 SMO steel in 4% NaCl in the absence

and presence of various concentration of SO2�4 and HCO�

3 ions, respectively. In case

of sulphate additions, it was found that increasing sulphate ion concentration in-

creased the crevice corrosion potential of the steel and dimensioned the hysteresis

loop (Fig. 10). This result indicates that sulphate has an inhibition effect on crevice

corrosion. The mechanism by which sulphate ion was inhibiting crevice corrosion

was through a supporting electrolyte effect [26]. The increase in the crevice corrosion

potential should be due to the competitive migration of SO2�4 and Cl�, with accu-

mulation of the critical concentration of Cl� needed being delayed.

Increasing the addition of sodium bicarbonate to chloride solution led to a sig-

nificant positive shift in the Ecrev and reduction of the hysteresis loop of the steel as

shown in Fig. 11. On the addition of 0.5 M sodium bicarbonate to 4% NaCl the

hysteresis loop was eliminated. On the forward potential sweep of the steel in 4%

NaCl in presence of 0.3 M sodium bicarbonate, it was found the initiation of small

anodic current peak at 420 mV. The magnitude of this peak increased with

increasing the concentration of bicarbonate ions. This current peak might be

10-7 10-5 10-3 10-1-600

-300

0

300

600

900

1200

1500

d c b a

E, m

V SCE

Current Density, (A/cm2)

(a) 0.0M (b) 0.1M (c) 0.5M (d) 1.0M

Fig. 10. PCAP curves of creviced sample of Type 254 SMO in 4% NaCl with potential scan rate 5 mV s�1

in the presence of (a) 0 M Na2SO4 (b) 0.1 M Na2SO4 (c) 0.5 M Na2SO4 (d) 1 M Na2SO4 at 70 �C.

10-8 10-6 10-4 10-2 100

-300

0

300

600

900

1200

1500

10-8 10-6 10-4 10-2 100-600

-300

0

300

600

900

1200

10-8 10-6 10-4 10-2 100-600

-300

0

300

600

900

1200

10-8 10-6 10-4 10-2 100

-300

0

300

600

900

1200

10-8 10-6 10-4 10-2 100-600

-300

0

300

600

900

1200

(a)

E,m

V SCE


(b)

E,m

V SCE


(c)

E,m

V SCE


(d)

E,m

V SCE


(e)

E,m

V SCE


Fig. 11. PCAP curves of creviced sample of Type 254 SMO in 4% NaCl with potential scan rate 5 mV s�1

in the presence of (a) 0 M NaHCO3 (b) 0.1 M NaHCO3 (c) 0.3 NaHCO3 (d) 0.5 M NaHCO3 (e) 1 M

NaHCO3 at 70 �C.



attributed to the formation of a very limited crevice corrosion which delayed when

the potential was swept to more positive potential.

4. Conclusions

The results of the present work allow the following conclusions to be drawn.

1. Crevice corrosion of Type 254 SMO stainless steel occurred in 4% NaCl solution

at CCT of 55 �C and there was no significant difference in temperature between

CCT and Tprot.

2. SEM micrographs indicated the association of pitting and crevice corrosion for

Type 254 SMO stainless steel in 4% NaCl solution at 90 �C.

3. The Ecrev of Type 254 SMO stainless steel decreased linearly with increasing thechloride ion concentration and crevice attack became more strong as shown by

SEM.

4. Lowering the pH value of 4% NaCl caused more aggressive crevice attack due to

increase in the local acidification inside the crevice.

5. The Ecrev of Type 254 SMO stainless steel did not change with the change of bro-

mide ions to chloride ions ratios at a fixed halide content of 4%.

6. Sulphate and bicarbonate were found to be strong inhibitors for crevice corrosion

and operate via a competitive migration mechanism.

Acknowledgements

E. A. Abd El Meguid wishes to thank Alexander von Humboldt foundation for

providing the equipments.

References

[1] H.I. Al Hossani, T.M.H. Saber, R.A. Mohammed, A.M. Shams El Din, Desalination 109 (1997) 25.

[2] A.M. Shams El Din, L. Wang, T.M.H. Saber, Br. Corros. J. 29 (1994) 58.

[3] J. Olsson, B. Wallen, Desalination 44 (1983) 241.

[4] B. Wallen, T. Abramsen, Fourth Asian Pacific Corrosion Control Conference Tokyo, 1985, p. 523.

[5] A. Mallica, A. Trevis, Proceedings of the Fourth International Congress on Marine Corrosion and

Fouling, Antibes, 1976, p. 351.

[6] R. Johnson, E. Bardal, J.M. Drugh, Proceedings of the Ninth Second Corrosion Congress, vol. 1,

Copenhagen, 1983, p. 371.

[7] R.C. Newman, T. Shahrabi, Corros. Sci. 27 (1987) 827.

[8] L. DeMecheli, A.H.P. Andrade, C.A. Barbosa, S.M.L. Agostinho, Br. Corros. J. 35 (2000) 297.

[9] J.W. Oldfield, W.H. Sutton, Br. Corros. J. 13 (1978) 104.

[10] S.E. Lott, R.C. Alkire, J. Electrochem. Soc. 136 (1989) 973.

[11] H.W. Pickering, R.P. Frankenthal, J. Electrochem. Soc. 119 (1972) 1297.

[12] K. Cho, H.W. Pickering, in: G.C. Frankel, R.C. Newman (Eds.), Critical Factors in Localized

Corrosion, The Electrochemical Society, Pennington, NJ, 1992, p. 407.

[13] M. Suleiman, L. Ragault, R.C. Newman, Corros. Sci. 36 (1994) 479.


[14] N.J. Laycock, J. Stewart, R.C. Newman, Corros. Sci. 39 (1997) 1791.

[15] S. Valen, P.O. Gartland, Corrosion 51 (1995) 750.

[16] T. Rogne, J.M. Drugli, S. Valen, Corrosion 48 (1992) 864.

[17] H.S. Isaacs, J. Electrochem. Soc. 120 (1973) 1457.

[18] R. Qvarfort, Corros. Sci. 29 (1989) 987.

[19] E.A. Abd El Meguid, A.A. Abd El Latif, J. Appl. Electrochem., in press.

[20] H.P. Hack, Mater. Perform. (June) (1983) 24.

[21] E.A. Abd El Meguid, N.A. Mahmoud, V.K. Gouda, Br. Corros. J. 33 (1998) 42.

[22] E.A. Abd El Meguid, Corrosion 53 (1997) 623.

[23] R.C. Newman, Corrosion 57 (2001) 1030.

[24] G. Ruijin, M.B. Ives, Corrosion 45 (1989) 572.

[25] Stockert, Boehni, Mater. Sci. Forum 44/45 (1989) 313.

[26] H.P. Leckie, H.H. Uhlig, J. Electrochem. Soc. 113 (1966) 1262.

Electrochemical and SEM study on Type 254 SMO stainless steel in chloride solutions

Documents

Transcript of Electrochemical and SEM study on Type 254 SMO stainless steel in chloride solutions