Erosion-corrosion of carbon steel in crude oil: velocity
effects on the erosion-corrosion map
G. H. Abdulrahman and M. M. Stack
Department of Production Engineering
Arabian Gulf Oil Company
Benghazi-Libya
and
Department of Mechanical and Aerospace Engineering
Strathclyde University,
James Weir Building,
75 Montrose St.,
Glasgow G1 1XJ, UK
Email:
Ghaith_23@yahoo.com
Phone No: 0913529460
margaret.stack@strath.ac.uk
1
Abstract
In this work, the effects of erosion-corrosion on carbon steel in two environments,
crude oil and crude oil/ 20% water environments containing Al2O3 particles were
investigated using an impinging erosion test rig, at two velocities and at a range of
impact angles and applied potentials. The results indicated that the corrosion
contribution increased with an increase in the percentage of reservoir water. It was
observed that the erosion rate changed as a function of impact angle and applied
potential and depended on the nature of the corrosion product formed on the surface
and the presence of the oil film.
Furthermore, increases in velocity altered the
erosion-corrosion mechanism significantly. Mechanisms of erosion-corrosion were
proposed based on the laboratory studies. The results were used to construct erosion–
corrosion maps showing mechanistic interactions, as a function of impact angle and
electrochemical potential, at the various exposure velocities.
2
1-Introduction
Erosion–corrosion in oil production depends on a range of factors present in
downhole oil wells, such as sand concentration, reservoir pressure, temperature, and
H2S and CO2 concentration. These conditions may lead to serious mechanical and
chemical degradation resulting in economic losses due to maintenance, leaks and
replacement of important components [1-4]. Sand production from reservoirs with oil
can be controlled by designing a Gravel Pack which prevents sand uptake as the oil is
processed from upstream to downstream conditions [5].
In some oilfields, sand content can be controlled by decreasing the velocity of the
production through controlling the choke size in the production process [5]. In such
conditions, it is important to determine the proportion of water in the environment, the
sand content, the operating electrochemical conditions such as potential, and the
properties of the particles, such as size, shape, concentration and impact angle.
In this paper, the effects of velocity, impact angle and applied potential were assessed
for carbon steel in a range of crude oil and oil/water slurries. Erosion-corrosion maps
were generated based on the results showing the variation in wastage and regime of
degradation as a function of these variables. The potential applications of the maps to
such materials issues in petroleum production are described in this paper.
2. Experimental details
2.1
Erosion-corrosion test methods
The erosion–corrosion tests were carried out using an impinging jet apparatus is
described elsewhere [7]. This consisted of a jet of particles in an aqueous flow
enabling the effect of erosion variables to be evaluated independently of each other.
The impact angle of the specimen could be varied by rotating the stationary specimen.
The slurry was composed of aluminium oxide (Al2O3) 150-300µm in oil and oil/20%
3
water, pH value of oil and mixed environment were 5 and 8.0 at temperature 500 C.
The test specimen was connected to an electrochemical cell as shown elsewhere (1).
The reference electrode was saturated calomel. Potentiodynamic polarization curves
were measured through sweeping the potential in a positive direction from −800 to
800 mV at a sweep rate of 200 mV min-1 during the test. Erosion–corrosion tests were
conducted at five applied potentials namely, -400 mV, 0 mV and 400mV (SCE) for 30
minutes using a computer controlled ACM potentiostat. The test material was carbon
steel supplied by Kelvin Steel Glasgow with chemical composition as percentage: C:
0.18, Mn 1.6, Si 0.55, Cr 0.25, Cu: 0.35, Ni: 0.3, S: 0.008. The chemical composition
of crude oil in ppm (mass) was (Ca: 33.26, Na: 4.26, K: 1.07, H2S: 0.0007).
The
dimensions of the specimens were 25mm × 10mm × 4 mm. The area exposed to
impingement jet was 0.19cm2, whilst the remaining area was covered by a coating in
order to ensure that all corrosion measurements related to the erosion-corrosion
process only.
Mass change measurements were made of the samples post testing using a Metter
electronic balance. The tests were carried out at two impact velocities i.e. 2.5 and 4.5
m s−1, for 30 minutes. The reproducibility of the experiments was estimated to be ±
5% calculated between two consecutive experiments. At the end of the test, the
samples were cleaned with distilled water to remove any deposited material.
Following exposure, the morphology of the eroded specimens was evaluated using
scanning electron microscopy (SEM).
3. Results
3.1 Electrochemical monitoring
Fig. 2 (a) shows impact velocity 2.5 m s−1 in the crude oil environment. The average
free corrosion potential (Ecorr) was between -405mV and -415 mV approximately
for all three impact angles and there was a general decrease in the current density at
all impact angles compared with oil/water environment Fig. 2 (b). This could be due
to the oil film protecting the surface of the specimen from corrosion by inhibiting
dissolution of ions of the steel in the hydrocarbon environment (as indicated by the
decrease in the current density [8]).
4
Conversely, the percentage of reservoir water in crude oil had a significant effect in
enhancing the corrosion.
Fig. 3 (a) shows that at an impact velocity 4.5 m s−1 in the crude oil environment
containing particles sized150-300µm, the current increased very slowly with increase
in impact angle from 15° to 45°, which is consistent with the findings of previous
research [8]. Fig. 3 (b) shows impact velocity 4.5 m s−1 in the 20% water with crude
oil environment. The current density was increased compared with the previous
impact velocity 2.5 m s−1 Fig. 2(b).
3.2. Volume loss and microscopy results
The total mass loss kec, corrosion and erosion contribution for carbon steel in the two
environments was recorded at impact velocities, 2.5, and 4.5m s−1. Tables 1-4 show
the results of calculation of volume loss for erosion contribution (ke), corrosion
contribution (kc) and total erosion-corrosion (kec) for different velocities with various
impact angles and applied potentials. For the volume loss results, kec represented the
measured erosion-corrosion rate. kc was calculated from the Faradic conversion of
the current density to mass loss. The value of ke, the erosion contribution, was
calculated from the equation:
kec= ke + kc
(1)
In the crude oil environment at impact velocity 2.5 m s−1, Fig. 4-6, the value of
corrosion contribution kc was significantly lower than the value of the erosion
contribution ke. The erosion-corrosion rate appeared to be independent of impact
angle. By contrast in the crude oil and oil/water conditions, Fig. 5-7 the total erosioncorrosion rate appeared to be a maximum at intermediate impact angles of 45o and at
potentials of
400mV. In the oil/water environment, the value of the corrosion
contribution (kc) was greater than that for erosion (ke). The exception was at 2.5
m s−1 and potential of -400mV, Fig.5 (a).
5
3.3. SEM analysis
Figures 8-9 show scanning electron micrographs of eroded carbon steel. The surface
morphologies were significantly affected by the impact velocity and impact angle in
both crude oil and oil/water environments.
For carbon steel in crude oil environment, there was a significant increase in
deformation due to particle impact, Fig. 8 (a). The surface of the specimens in the
crude oil environment led to less degradation compared to that observed the oil/water
conditions, Fig. 9 (a).
4. Discussion
4.1 Trends on the effect of mass change as a function of impact angle and applied
potential
The results for carbon steel in the two environments indicate that there is a significant
reduction in the corrosion current density (Figures 2-3(a-b) when the experimental
conditions are changed from oil/water to crude oil environments. This indicates that
corrosion contribution is reduced significantly in crude oil environments and this can
be attributed to a decrease in the diffusion of iron (Fe) ions in the fully hydrocarbon
environment [8].
In addition, the diffusion of oxygen is higher in crude oil than in oil/water and this is
the possibly the reason why the cathodic current densities are higher than the anodic
current densities in such conditions (Figures 2-3(a). In the oil/water environments, in
these conditions, a maximum corrosion current is observed at an impact angle 45o
(figures 2-3(b). This indicates that in oil/ water environment, where formation of a
corrosion product is facilitated, particle impacts angle at 45o tend to cause higher
degradation rates, unlike that which is observed in the oil environment containing
particles where the maximum wastage recorded is at 45o and 90o (Figures 2-3(a).
6
In the crude oil and combined environment, Fig. 4-7(a-c), there is a slightly higher
mass loss at 400 mV, Fig. 4-7 (c) compared to that observed at lower potentials Fig.
4-7 (a). The trends for the effect of impact angle indicate that the maximum is at 45o
and 90o consistent with results on the polarization data, Fig. 2-3(a-b).In the oil/ water
environment, there is a clear indication of a maximum erosion-corrosion rate at
impact velocity 4.5 m s−1, Fig. 7(a-c).
4.2. Erosion-corrosion maps
Erosion-corrosion (kec) maps were constructed to show that the transition between
wastage regimes i.e. with the low value defined as less or equal to 6 mg cm −2 h−1 ,
medium between 6 and 50 mg cm −2 h−1 and high greater or equal to 50 mg cm −2 h−1
(1-4).
Figures 10 (a-b) show carbon steel at constant impact velocity of 2.5 m s−1 in the
crude oil and mixed environment. It is interesting to see that the low wastage regimes
dominate at all impact angles and applied potentials, and there is no evidence of the
presence of a medium wastage regime on the map. For carbon steel in the crude oil
environment at impact velocity 4.5 m s−1 Fig. 11 (a), it can be seen that the low
wastage regime dominates and there is no evidence of medium wastage on the
specimen with increase in impact velocity. Fig. 11 (b) shows that in the combined
environment, the medium wastage regime predominates. This is attributed to the
relatively high value of the corrosion contribution kc at 4.5 m s−1.
Erosion-corrosion additive-synergism maps for carbon steel in the crude oil and
oil/water environments containing particles have been constructed. Tables 1-4 show
the values of Δke /Δkc ratio for the carbon steel in the different environments. They
show the differences between the boundaries as a function of impact angle and
applied potential. For the fully hydrocarbon conditions, Fig. 12(a), it is interesting to
see that the synergistic effect has a significant effect on the specimen at 2.5 m s−1 .
On the other hand, Fig.12(b), shows carbon steel in the combined environments. It is
clear that the percentage of synergistic effect on the specimen is decreased compared
7
with that observed in the crude oil environment Fig. 12(a), while the additivesynergistic regime becomes dominant across the entire whole map. This is attributed
to the presence of the passive film in such conditions. From this map, it is clear that
both erosion and corrosion enhance each other over this window of conditions.
Fig. 13(a) shows carbon steel in the crude oil environment at 4.5 m s−1. It can be seen
that the synergistic effect dominates the entirety of the map. However, Fig. 13(b ), in
the crude oil/20% water environment, it can be seen that the boundaries change to
additive-synergistic in these conditions.
Erosion-corrosion mechanism maps have been constructed for carbon steel in crude
oil and oil/water environments. Fig. 14(a), shows at constant impact velocity of 2.5
m s−1 for carbon steel in the crude oil environment. It is observed that erosion–
passivation dominates in all areas between impact angles 15° - 90° and between
applied potentials -400mV to 400mV.
However, in the crude oil/20% water
environment, the passivation-erosion regime occupies the area in anodic conditions,
which can be attributed to the passive film forming on the surface of the specimen.
At impact velocities of 4.5 m s−1 Fig.15 (a), it is interesting to observe that the erosionpassivation regime predominates for the fully hydrocarbon environment. In oil/20%
water at similar velocities, Fig. 15 (b), it is clear that passivation–erosion regime
predominates. Also, there is no evidence of the presence of erosion-passivation effect
on the map with increasing in impact velocity from 2.5 m s−1 to 4.5 m s−1 , indicating
that passivation has a more significant effect on the erosion-corrosion process, in
these conditions, as evidenced also by the polarization and volume loss data above.
Clearly, erosion-corrosion maps are important tools which can be used to predict
wastage in such conditions. The results on the effect of velocity indicate a significant
change depending on the conditions. Further work will be to assess the boundaries of
such maps, over a wider range of variables for oil and gas processing, such that a
materials and process parameter map be constructed for such environments.
8
5. Conclusions
(i)
(ii)
(iii)
The effects of impact angle and electrochemical potential on the
erosion–corrosion of carbon steel have been assessed in crude oil and
oil/water environments containing particle sizes ranging from
150  300 m .
Erosion-corrosion wastage, additive-synergism and mechanism maps
have been constructed based on the results.
The results have indicated that the erosion-corrosion regimes are
highly dependent on the exposure conditions, with the enhanced
passivation in the water containing environments, resulting in either
an increase and reduction in the overall wastage, depending on the
exposure conditions.
Potentiostat
RE
Ejector Body
Inlet Nozzle
W.E
A.E
Exit Nozzle
Test Specimen
Solution
Fig.1: Electrochemical connection in the slurry erosion test.
9
800
15°
600
600
400
200
Potential (mV)
Potential (mV)
800
90°
45°
0
-200
45°
90°
400
15°
200
0
-200
-400
-400
-600
-600
-800
-800
0.0001
0.01
0.001
0.1
0.0001
-2
0.01
0.1
1
-2
Current (mA cm )
Current (mA cm )
(a)
(b)
Figure (2) Polarization curves for carbon steel at various impact angles in (a) crude oil
and (b) crude oil/ 20% water at impact velocity 2.5 m s−1.
800
800
45°
600
600
400
200
Potential (mV)
Potential (mV)
90°
15°
0
-200
400
0
-600
-600
0.001
0.01
0.1
15°
-200
-400
0.0001
90°
200
-400
-800
45°
-800
-2
Current (mA cm )
0.0001
0.01
0.1
-2
Current (mA cm )
10
1
(a)
(b)
2.2
-1
1.8
Ke
Kc 2.4
Kec
2.0
Ke
Kc
Kec
2.2
2.0
-1
-2
1.6
1.4
1.2
1.0
0.8
0.6
Volume loss .mg cm .h
-2
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
Ke
Kc
Kec
Volume loss .mg cm .h
-2
Volume loss .mg cm .h
-1
Figure (3) Polarization curves for carbon steel at various impact angles in (a) crude oil
and (b) crude oil/ 20% water at impact velocity 4.5 m s−1.
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.4
15°
45°
15°
90°
45°
90°
15°
Impact angle
Impact angle
(a)
45°
90°
Impact angle
(b)
(c)
Fig.4: Volume loss as function of impact angle for carbon steel in crude oil at
2.5 m s−1impact velocity (a) -400mV (b) 0mV (c) 400mV
Ke
Kc
Kec
2.6
-2
2.0
1.8
1.6
1.4
1.2
-1
2.2
2.0
1.8
1.6
1.4
1.2
1.0
45°
90°
Impact angle
2.5
2.0
1.5
1.0
1.0
15°
0.8
15°
45°
90°
Impact angle
(a)
Ke
Kc
Kec
3.5
3.0
-2
-1
2.4
Volume loss .mg cm .h
-2
Volume loss .mg cm .h
-1
2.4
2.2
Ke
Kc
Kec
2.8
Volume loss .mg cm .h
2.6
(b)
15°
45°
Impact angle
(c)
Fig.5: Volume loss as function of impact angle for carbon steel in oil /20% water at
2.5 m s−1impact velocity (a) -400mV (b) 0mV (c) 400mV
11
90°
6.0
Kc
5.5
5.5
5.0
5.0
Kec
3
2
-1
4.5
-2
-2
4
Volume loss .mg cm .h
Volume loss .mg cm .h
-1
-1
5
Ke
6.0
4.0
3.5
3.0
2.5
2.0
1.5
1
Volume loss .mg cm .h
Ke
Kc
Kec
1.0
15°
45°
90°
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
15°
Impact angle
45°
90°
15°
Impact angle
(a)
45°
90°
Impact angle
(b)
(c)
Fig.6: Volume loss as function of impact angle for carbon steel in crude oil at
4.5 m s−1impact velocity (a) -400mV (b) 0mV (c) 400mV
Ke
Kc
Kec6.5
6.0
5.5
6.0
3.0
2.5
2.0
-2
5.0
4.5
4.0
3.5
3.0
2.5
1.5
15°
45°
90°
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.0
15°
Volume loss .mg cm .h
3.5
6.5
6.0
5.5
Volume loss .mg cm .h
4.0
7.0
-1
-1
4.5
-2
Volume loss .mg cm .h
-1
5.0
-2
Ke
Kc
Kec
45°
90°
2.0
Impact angle
Impact angle
(a)
(b)
15°
45°
Impact angle
(c)
Fig.7: Volume loss as function of impact angle for carbon steel in oil /20% water at
4.5 m s−1impact velocity (a) -400mV (b) 0mV (c) 400m
12
90°
(a)
(b)
(c)
13
(d)
Fig.8: Scanning electron micrographs of eroded carbon steel test specimen at 4.5
m s−1, impact angle 90° (a) in crude oil (b) analysis of the spectrum-1 (c) analysis of
the spectrum-2 (d) analysis of the spectrum-3
(a)
(b)
(c)
14
(d)
Fig.9: Scanning electron micrographs of eroded carbon steel test specimen at
4.5 m s−1, impact angle 90° in (a) oil /20% water (b) analysis of the spectrum-1 (c)
analysis of the spectrum-2(d) analysis of the spectrum-3
90
Impact angle
Impact angle
Low Wastage
45
90
45
Low Wastage
15
15
-500
-400
-500
400
0
E(mV)
-400
(a)
400
0
E(mV)
(b)
Figure (10): Erosion-corrosion wastage maps for carbon steel in (a) crude oil (b) crude oil / 20%
of water at 2.5 m s−1
Low Wastage
45
45
15
15
-500
90
Low Wastage
90
Impact angle
Impact angle
Medium Wastage
-400
0
E(mV)
400
-500
(a)
-400
0
E(mV)
(b)
15
400
Fig.11: Erosion-corrosion wastage maps for carbon steel at 4.5 m s−in (a) crude oil (b)
oil /20% water
90
Impact angle
Impact angle
90
Synerg
istic Dominated
Synergistic
Dominated
45
45
Additive-Synergistic
Additive-Synergistic
15
15
Synergistic
Additive
-500
-400
-500
400
0
0
E (mV)
-400
E(mV)
(a)
400
(b)
90
90
Impact angle
Impact angle
Fig.12: Erosion-corrosion additive-synergism maps for carbon steel at 2.5m s−1 in (a) crude oil (b)
oil /20% water.
45
45
Additive-Synergistic
Synergistic Dominated
15
15
Additive-Synergistic
Additive
-500
-400
0
-500
400
E(mV)
16
-400
0
E (mV)
400
(a)
(b)
Fig.13: Erosion-corrosion additive-synergism maps for carbon steel at 4.5m s−1 in (a) crude oil
(b) oil /20% water.
45
15
Erosion-Passivation
90
Impact angle
Impact angle
Erosion-Passivation
90
45
Passivation-Erosion
15
-500
-400
0
E(mV)
400
-500
-400
0
E(mV)
400
90
Impact angle
Impact angle
(a)
(b)
−1
Fig.14: Erosion-corrosion mechanism maps for carbon steel at 2.5 m s in (a) crude oil (b) oil /20% water.
45
Erosion-Passivation
45
Passivation-Erosion
Passivation-Erosion
15
-500
90
15
-400
0
E(mV)
400
-500
-400
0
E(mV)
(a)
(b)
Fig.15: Erosion-corrosion mechanism maps for carbon steel at 4.5 m s−1 in (a) crude oil
(b) oil /20% water.
17
400
Tables.1:Volume loss as function of impact angles for carbon steel in crude oil at 2.5
m s−1 (a) -400mV (b) 0mV (c) 400mV.
(a)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
1.429
1.658
1.059
3.21E-01
3.42E-01
5.91E-01
1.75
2
1.65
4.4517
4.8479
1.7918
4.177
4.54
1.676
(b)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
1.455
1.77
1.44
3.95E-01
3.40E-01
4.10E-01
1.85
2.11
1.85
3.68
5.20
3.512
4.63 4
5.23
4.837
(c)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
1.556
1.947
1.73
4.24E-01
3.57E-01
4.70E-01
1.98
2.304
2.2
3.669
5.45
3.68
4.376
6.107
4.836
Tables.2:Volume loss as function of impact angle for carbon steel in oil /20% water at
2.5 m s−1 impact velocity (a) -400mV (b) 0mV (c) 400mV.
(a)
Impact
Ke(mg
Kc(mg
Kec(mg
angle
Ke/Kc
cm −2 h−1) cm −2 h−1)
cm −2 h−1)
Δke/Δkc
15°
1.11E+00
1.189
2.3
1.070
3.55 4
45°
1.21E+00
1.289
2.5
1.0644
0.91
90°
1.03E+00
1.399
2.43
1.3567
2.76
(b)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
1.089
0.949
0.849
1.51E+00
1.75E+00
1.65E+00
2.6
2.7
2.5
0.72 8
0.54
0.514
0.88
0.209
0.527
(c)
18
Impact
angle
15°
45°
90°
Ke(mg
cm −2
h−1)
0.979
1.549
0.819
Kc(mg
cm −2 h−1)
1.77E+00
1.85E+00
1.83E+00
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
2.75
3.4
2.65
0.55
0.836
0.447
0.483
0.725
0.398
Table.3: Volume loss as function of impact angles for carbon steel in crude oil
4.5 m s−1impact velocity (a) - 400mV (b) 0mV (c) 400mV
(a)
Impact
Ke(mg
Kc(mg
Kec(mg
angle
Ke/Kc
cm −2 h−1) cm −2 h−1) cm −2 h−1)
Δke/Δkc
15°
7.50E-01
4.25
5
5.66
6.0
45°
8.00E-01
4.62
5.42
5.77
5.816
90°
8.23E-01
3.827
4.65
4.65
5.889
(b)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
4.647
4.859
4.332
8.53E-01
8.91E-01
8.68E-01
5.5
5.75
5.2
5.449
5.45
4.99
7.33
5.88
6.46
(c)
Impact
angle
15°
45°
90°
Ke(mg
cm −2
h−1)
Kc(mg
cm −2 h−1)
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
4.55
4.9
4.2
9.00E-01
1.00E+00
1.20E+00
5.45
5.9
5.4
5.055
4.9
3.5
7.5
5.26
4.08
Table.4: Volume loss as function of impact angles for carbon steel in oil /20% water
at 4.5 m s−1impact velocity and particle size 150  300 m (a) - 400mV (b) 0mV (c)
400mV
(a)
Impact
Ke(mg
Kc(mg
Kec(mg
angle
Ke/Kc
cm −2 h−1)
cm −2 h−1)
cm −2 h−1)
Δke/Δkc
15°
3.37E+00
2.53
5.9
0.75
0.57
45°
3.60E+00
2.4
6
0.66
0.29
90°
3.52E+00
1.98
5.5
0.56
0.42
(b)
Impact
angle
15°
45°
90°
Ke(mg
cm −2 h−1)
2.4
2.05
1.9
Kc(mg
cm −2 h−1)
4.00E+00
4.45E+00
4.30E+00
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
6.4
6.5
6.2
0.6
0.46
0.44
0.37
0.107
0.3
(c)
19
Impact
angle
15°
45°
90°
Ke(mg
cm −2
h−1)
2.42
2.23
2.08
Kc(mg
cm −2 h−1)
4.23E+00
4.55E+00
4.42E+00
Kec(mg
cm −2 h−1)
Ke/Kc
Δke/Δkc
6.65
6.78
6.5
0.57
0.49
0.47
0.457
0.191
0.446
References
[1] M. M. Stack, T. M. Abd El Badia, on the construction of erosion-corrosion maps
for wc/co-cr-based coatings in aqueous conditions, Wear 261 (11-12) (2006)1181–
1190.
[2] M. Stack, G. Abdulrahman, Mapping erosion-corrosion of carbon steel in oil
exploration conditions: Some new approaches to characterizing mechanisms and
Synergies, Tribology International, 43 (7) (2010) 1268-1277.
[3] M. M. Stack, S. Zhou and R.C. Newman, Characterization of synergistic effects
between erosion and corrosion in an aqueous environment using electrochemical
techniques. Corrosion Science, 52 (1996) 934-946.
[4] M.M .Stack and Pungwiwat N, Erosion–corrosion mapping of Fe in aqueous
slurries: some views on a new rationale for defining the erosion–corrosion interaction,
Wear 256 (5 ) (2004) 565-576.
[5]
R .Hamzah, D.J Stephenson and J.E. Strutt, Erosion of material used in
petroleum production, Wear 186 (187) (1995) 493-496.
[6] Yu .Fang and Guoan Zhang, Mechanical properties of CO2 corrosion product
scales and their relationship to corrosion rates, Corrosion Science 50 (2008) 2796–
2803.
[7] J.B. Zu, I.M. Hutchings and G.T. Burstein, Design of a slurry erosion test rig,
Wear140 (2) (1990)331–344.
[8] B.R Tian and Y.F. Cheng electrochemical corrosion behaviour of X-65 steel in
the simulated oil sand slurry. I. Effects of hydrodynamic condition, Corrosion Science
50 (2008) 773-779.
[9] G.T .Burstein, Y. Li and I.M. Hutchings, The influence of corrosion on the
erosion of aluminium by aqueous silica slurries, Wear 186-187 (Part 2) (1995) 515 –
522.
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