International Journal of Mechanical and Production
Engineering Research and Development (IJMPERD)
ISSN(P): 2249-6890; ISSN(E): 2249-8001
Vol. 7, Issue 4, Aug 2017,291-306
© TJPRC Pvt. Ltd.
ANINVESTIGATION OF LOCALIZED CORROSION OFAL 2024 UNDER
FULLYIMMERSED CONDITION OF CHLORIDE (HCL) MEDIA
ANIL KUMAR 1 & VINAY SAINI 2
1 Research Scholar, Department ofMechanical Engineering, Chandigarh University, Punjab, India
2 Assistant Professor, Department of Mechanical Engineering, Chandigarh University, Punjab, India
ABSTRACT
Al 2024 is an important engineering material, which is used in aerospace, marines, & automotive field. It is
employed in many process industries cause of low density, High strength, corrosion resistance and low cost. The present
study aims to investigate the corrosion behavior ofAl 2024, under varying proportion of normality’s and temperatures
variation, respectively in chloride media. Corrosion testing is evaluated through fully immersion weight loss method in
HCL solution with different Normality’s that is 0.25N,0.50N,0.75, and 1N, at variation in temperature 300,600, 800for 6,
12, 18, to 36 days. Corrosion characterization is done to investigate the effect of microstructure on its performance, and
to study the effect of temperature on corrosion rate. The change in micro hardness is observed to be quite significant
after being exposed to the chloride Acidic solution having pH 1 at different temperature for regular interval of 6 days
over a period of 36 days. More-over, morphology and chemical compositions of corrosion behavior ofAl 2024 under
varying normality and temperature condition was analyzed through SEM and EDS.
KEYWORDS: Aluminum 2024, Localized Corrosion, HCL Solution, Weight Loss, Corrosion Rate, SEM & EDS
TRAN5
STELLAR
• Journal Publications • Research Consultancy
Received: Jun 19, 2017; Accepted: Jul 10, 2017; Published: Jul 31, 2017; Paper Id.: IJMPERDAUG201729
INTRODUCTION
Now days, the Aluminum alloy has been given important role as construction materials in the military and
private sector. Aluminum alloy has low density, High strength, corrosion resistance and low cost. Low density
material has huge demand on aerospace industries to development of exotic alloys. Due to limitations on satisfying
the consumer's needs, their potential utilization has not yet been fully realized. The cause has been standard
method of testing such materials for corrosion and corrosion resistance, everyone not satisfying with manufacture,
fabrication and design [l].This method was not industry oriented, but rather environment oriented, such as
materials qualification tests were performing on the standards there were available. Now, Technology has been
advanced to change this sort of approach [2]. The aluminum alloys that are used in several Industries and their
tests used must meet specific requirements [3]. The uses of the metal are extremely diverse due to unusual
properties. Aluminum alloy such as used for heat-treated parts, airfoil and fuselage skins, extrusions, and fittings
or aircraft fuselages, door skin, dorsal fin and trailing edge panel, automobile body as well as truck wheel rims and
other structural application, due to their high strength and weight ratio, higher ductility and corrosive resistance
[4]. Alloy can be affected from corrosion like as Pitting corrosion, Inter-granular Corrosion, stress corrosion
cracking, Exfoliation corrosion, and galvanic corrosion [3]. Although corrosion mechanism of A1 2024have been
previously investigated in chloride media, but for NACL, basic solution as per several studies was investigated [5-
6]. Pitting corrosion is observed as A1 alloys exposed to in aqueous environment. Traditionally, the cause of pitting
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Anil Kumar & Vinay Saini
corrosion has been attacked on the passive film that takes shape on a metal surface. [7-8 to 9]
LITERATURE REVIEW
Hydrochloric acid is widely utilized in pickling of steel and aluminum structures, and acid cleaning, de-scaling
processes, which lead to substantial loss of the metal due to corrosion reaction. Hydrochloric acid, in presence of seawater
leads to formation of growing chloride ions. So, these donating free chloride ions (Cl-) in an aqueous solution attack on
metals, as a result of corrosion material get failure [10]. Chloride ions are usually extremely electro-negative and they are
very reactive with sealed compounds and elements. This responsiveness is part of its usefulness, which is countermined by
defiling, whereas, stainless steel is implicated. Although chloride is known to be the elemental agent of pitting attack, it is
not possible to found a single decisive chloride value for the metals and alloys [11]. Pitting is only a breakdown of the
passive layer, observed by localized corrosion that create pits, in steel vessels or pipes.
James et al [12] had studied the inhibition of the corrosion of aluminum in HCL solution by pyridoxol
hydrochloride, by using weight loss method and gesso-metric techniques are used. The inhibition efficiency was increased
with increasing inhibitor absorption and decrease with increase in temperature. Some of other investigation of the anodic of
the grains part can be assigning to a high absorption of solute atoms in this region, as equated to grain interior found in [13-
14].
V. Guillaumin et al [5] had studied the corrosion behavior of A1 2024 T351 alloy in 1 morality (NACL) solution.
This work was to interpret the alloy towards inter-granular corrosion and localized corrosion from potential-kinetic
Polarization curve. Whereas, G.S Chen et al [15] had studied the use of constituent particle in the pitting corrosion of A1
2024-T3, that was to investigated and correlate between characteristics of the particle and localized corrosion behavior.
This experiment was conducted on air frame material A1 2024-T3 in 0.5M sodium chloride solution (NACL).
The present study aims to investigate the corrosion behavior of A1 2024 under different normality’s at variation in
temperature. ASTM standard by fully immersion weight loss method in HCL solution is with different Normality’s that is
0.25N, 0.50N, 0.75, and 1N, at variation in temperature 30°, 60°, 80° for 6, 12, 18, to 36 days. Corrosion characterization is
done to investigate the effect of microstructure on its performance. The change in micro hardness is observed to be quite
significant after exposure to the deposits at different temperature for regular interval of 6 days over 36 days.
EXPERIMENTAL PROCEDUR
Material and Method
A1 2024 is an alloy with coppers, the main element. Due to poor corrosion resistance, we can weld this only
through friction welding. This material can be used in aerospace and aircraft, door skin, structures, fuselage, trailing edge
panels, dorsal fins, truck wheels rims, and crew machine products. Chemical composition or mechanical compositions are
shown in table 1.
Table 1: Chemical Composition wt (%)
Alloy
A1 2024
Component
AL
Mg
Si
Ti
Cr
Mn
Fe
Cu
Zn
Nominal
93.50
1.8
0.50
0.15
0.10
0.9
0.50
4.9
0.25
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
293
Table 2: Mechanical Properties
Properties
Metric
Imperial
Elastic modulus
80 G p a
10152 toll603 K s i
Passion ratio
0.33
0.33
Sample Preparation
Corrosion sample was prepared from a block of AL2024 alloy of dimensions 100mmx70mmx20 mm thick
rectangular bar. Specimens were prepared by cutting machine in to this dimensions 37mmx33mmx20mm.The surface was
polished with the diamond paste 3um or emery paper 320-400-600-2000 grade to get a starch free smooth surface and
double polishing machine was used for surface finishing. Specimen was shown in figure 1.
Figure 1: Showing the Specimen
Sample Cleaning Procedure
Specimens before experiment were cleaned with acetone or ethyl alcohol, distilled water and using the pickling
solution. After cleaning, the specimens were kept in desiccators to remove the moisture form specimen. Then, the weight
of each specimen was measured by advance four digits weighing machine. The weight of each specimen was found in
grams.
Corrosion Test Procedure
A1 2024 was used in exposure studies the size of specimens was 36mmx34mmxl9mm thickness. Then material
was soaked in glass beaker having volume of 250ml, in whichlOOml corrosive acidic HCL solution having pH lwas
prepared in different normality 0.25, 0.50, 0.75, 1N. After that, these corrosive solution were utilized to carry corrosion
study on various temperatures 30, 60, 80 to study the rate of corrosion utilizing weight loss method. The specimen samples
were regularly weighed after initiation over interval of 6 day for a period of 36 days exposure to HCL solution with pH 1,
as shown in figure 2. And figure 3.The samples were weighed periodically, after a regular interval of 6 days for continuous
36 days exposure to HCL solution with PH 1.
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Figure 2: Test Specimen in HCL Solution Figure 3: Test Specimen in Different Temperature
The specimen was fully immersed 3.5cm below the surface in the solution. The loss in weight of specimen sample
was measured after being exposed to corrosive HCL solution. After dissolved the specimen were cleaned with acetone or
ethyl alcohol, distilled water and the pickling solution. After cleaning, the specimen was kept in desiccators to remove the
moisture from specimen. Then, the weight of each specimen was measured by advance four digits weighing machine for
interval of 6 day, for a period of 36 days exposure to HCL solution with pH 1; in figure 4 and figure 5.
After Corrosion Specimen
Figure 5: Specimens Weight Measure
After the corrosion test corroded surface of the sample were studied under scanning electron microscope.
Before Corrosion Specimen
Figure 4: Corrosion Test Specimen
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
Test Procedure
295
Figure 6
Measurement of Surface Roughness and Micro-Hardness
A roughness tester is used to determine the surface texture or surface roughness of a material accurately.
A roughness tester shows the measured roughness depth (Rz) as well as the mean roughness value (Ra) in micrometers or
microns (pm) Shown in figure 6.The surface roughness of A1 2024 material is 0.62 to 0.66 microns.
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The hardness of AL 2024 alloy was measured by micro Vickers hardness testing machine using 19mm thickness
of aluminum. The hardness test was employed on five different specimens. A load of 1KG was used to determine the
hardness of the material, because the material is very soft Shown in figure 7.
RESULTS AND DISCUSSIONS
The results of weight loss and corrosion rate for A1 2024 corrosion in 0.25N, 0.50N, 0.75N, 1N HCL solution with
variation in temperature are shown in Figure 8(a), (b), (c), (d). It can be seen that the increase in temperature and acid
absorption results in increase the corrosion rate shown in the graph. Therefore, absorption of CL ions destroys the passive
film, which is tends to insulate the metal from the corrosive film. Corrosion rate of the material due to constitution of pits
crack on the surface as absorbed on the sample. It was observed that corrosion rate decreases due to the intermetallic
region. Severe Pitting corrosion was observed in the material surface, which is associated with the particle- matrix
interface.
Effect of Corrosion on Weight Loss Due To Different With Normality and Temperature Variation
The corrosion behavior of A1 2024 in 0.25 N normality’s at variation of temperature 30°, 60°, 80°for interval of 6,
12, 18, 24, 30 and 36 days was observed. Effect of temperature variation in 0.25N normality’s on weight loss of A1 2024 in
HCL solution shown in Figure 8(a), showing the weight loss with days on temperature variation of 0.25N normality, and
sample was fully immersed in solution HCL of different normality. The total weight loss % of specimen (1) 0.25N on
30°temperatures in 36 days is 2.75% and specimen (5) total weight loss % in 0.25N on 60° temperatures in 36 days is
3.82% and specimen (9) total weight loss % in 0.25N on 80° temperatures in 36 days is 10.29%. It can be seen that the total
weight loss % is increased with the increase in temperature shown in graph. The corrosion behavior of A1 2024 in 0.50 N
normality’s at variation of temperature 30°, 60°, 80° for interval of 6, 12, 18, 24, 30 and 36 days. Effect of temperature
variation in 0.50N normality’s on weight loss of A1 2024 in HCL solution shown in Figure 8(b). The total weight loss % of
specimen (2) in 0.50N on 30°temperatures in 36 days is 4.28% and specimen (6) total weight loss % in 0.50N on 60°
temperatures in 36 days is 14.40 % and specimen (10) total weight loss % in 0.50N on 80° temperatures in 36 days is
18.03%. It can be seen that the total weight loss % increases with the increase in temperature shown in graph. The
corrosion behavior of A1 2024 in 0.75 N normality’s at variation of temperature 30°, 60°, 80°for interval of 6, 12, 18, 24, 30
and 36 days. Effect of temperature variation in 0.75N normality’s on weight loss of A1 2024 in HCL solution shown in
Figure 8(c). The total weight loss % of specimen (3) in 0.75N on 30°temperatures in 36 days is 5.54% and specimen (7)
total weight loss % in 0.75N on 60° temperatures in 36 days is 17.21 % and specimen (11) total weight loss % in 0.75N on
80° temperatures in 36 days is 27.64%. It can be seen that the total weight loss % is increase with the increase in
temperature shown in graph. The corrosion behavior of A1 2024 in 1 N normality’s at variation of temperature 30°, 60°,for
interval of 6, 12, 18, 24, 30 and 36 days. Effect of temperature variation in 1N normality’s on weight loss of A1 2024 in
HCL solution shown in Figure 8(d). The total weight loss % of specimen (4) in 1N on 30°temperatures in 36 days is 8.99%
and specimen (8) total weight loss % in 1N on 60° temperatures in 36 days is 22.65 %.
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
297
IMumber of days
Temp 30
Temp 60
Temp 30
Figure 9(a): 0.25N
Figure 9(b): 0.50N
Figure 9(c): 0.75N Figure 9(d): 1N
The interval of time 6, 12, 18, to 36 days the weight loss increased gradually caused due to increase in
temperature, therefore, rose in acid concentration. The corrosion behavior of the A1 2024 due to the constitution of pits
cracks on the surfaces as absorbed on the sample. It can be seen that higher concentration of HCL ions destroy the passive
film of the surface, which as tends to insulate the metal from of corrosive solution. A similar pattern was absorbed in
weight loss of A1 2024 on different normality, whereas, with increased temperature, the weight loss was seen due to
corrosion seen in graph.
Effect of Normality Variation on Weight Loss of A1 2024 Held in Specific Temperature
The corrosion behavior of A1 2024 in different normality’s at variation on temperature 30°for interval of 6, 12, 18,
24, 30 and 36 days was observed. Effect of normality’s variation 0.25N, 0.50N, 0.75N, 1N normality’s on weight loss of A1
2024 in HCL solution shown in figure 9(a) shows the weight loss with days on normality variation of 0.25N, 0.50N, 0.75N,
1N normality and sample was fully immersed in HCL solution on 30° temperatures. First 6 days, the weight loss increased
gradually and after 12 days weight loss increased. The corrosion behavior of the A1 2024 due to the constitution of pits
cracks on the surfaces. A similar pattern was absorbed in weight loss of A1 2024 in different normality, whereas with
increase in solution the weight loss was seen due to corrosion on 30° temperatures seen in graph.
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16
0 20 40
Number of days
0.25IM
0.50N
0.75N
1N
Figure 10(b): 60° Temperature
Figure 10(c): 80°Temperature
Effect of normality’s variation 0.25N, 0.50N, 0.75N, 1N normality’s on weight loss of A1 2024 in HCL solution
shown in figure 9(b) shows the weight loss with days on normality variation of 0.25N, 0.50N, 0.75N, 1N normality and
sample was fully immersed in HCL solution on 60° temperatures. The first 6 days, the weight loss increased gradually and
after 12 days weight loss increased in 0.25N normality’s on temperature 60° and normality’s variation 0.50Non 60°
temperatures in 6 days the weight loss increased and another after 12 days weight loss increased due to corrosion and
therefore, 0.75 normality or 1N on 60° temperatures in 6 days, weight loss increased and after 12 days weight loss
increased and 1N in 6 days the weight loss increased and after 12 days the weight suddenly increased, a similar pattern
absorbed due to corrosion, it can be seen that in graph. The effect of normality’s variation 0.25N, 0.50N, 0.75N,
normality’s on weight loss of A1 2024 in HCL solution shown infigure9(c) showing the weight loss with days on normality
variation of 0.25N, 0.50N, 0.75N, normality and sample was fully immersed in HCL solution on 80° temperatures. The first
6 days, the weight loss increased gradually and after 12 days weight loss increased in 0.25N normality’s on temperature 80°
and normality’s variation 0.50N on 80° temperatures, in 6 days the weight loss increased and another after 12 days weight
loss increased due to corrosion and therefore, 0.75 normality on 80° temperatures in 6 days, weight loss increased and after
12 days weight loss increased, a similar pattern absorbed due to corrosion, it can be seen that in graph. The corrosion
behavior of al 2024 due to the constitution of pits cracks on the cracks.
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
Corrosion Rate
299
Temperature has a great effect on the corrosion phenomenon. Mostly, the corrosion rates increase with increase of
temperature. The total corrosion rate can be calculated for 36 days. The Corrosion rate unit taken was in (mm/py) i.e.
(65.789 mm/py)
Corrosion Rate can be calculated using
C.R = KxW
AxT x D (Equationl)
Where C.R = is the Corrosion rate, K = Constant, W = Total weight loss, A = Surface area of the specimen, T =
Time, D = Density of the metal in gm/cm 2
Effect of Corrosion on Corrosion Rate Due to Different With Normality and Temperature Variation
The corrosion behavior of A1 2024 in variation of normality’s on temperature 30°for interval of 6, 12, 18, 24, 30
and 36 days was observed. Effect of normality’s variation 0.25N, 0.50N, 0.75N, 1N normality’s on corrosion rate of A1
2024 in HCL solution shown in figure 10(a) shows the corrosion with days on normality variation of 0.25N, 0.50N, 0.75N,
1N normality, and sample was fully immersed in HCL solution on 30° temperatures. First 6 days, the weight loss increased
gradually and after 12 days weight loss increased. The corrosion behavior of the A1 2024 was due to the constitution of pits
cracks on the surfaces. A similar pattern absorbed in weight loss of A1 2024 in different normality, whereas with increased
the solution the corrosion rate was seen due to acid concentration on 30° temperatures seen in graph. In figure 10(b) and
figure 10 (c) first 6 days the weight loss increased gradually and after 12 days weight losses increased.
The corrosion behavior of the A1 2024 was due to the constitution of pits cracks on the surfaces. It can be seen that
higher concentration of HCL ions destroys the passive film of the surface, which inclines to insulate the metal from of
corrosive solution. A similar pattern absorbed in corrosion rate of A1 2024 on different normality, whereas with increased
temperature, the corrosion rate was seen due to corrosion seen in graph.
Figure 11 (a): 30° Temperature Figure ll(b): 60° Temperature
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Figurell (c): 80°Temperature
Effect of Normality Variation on Corrosion of A12024 Held in Specific Temperature
Effect of temperature variation in 0.25N normality’s on corrosion rate of A1 2024 in HCL solution shown in
Figure ll(a) shows the corrosion rate with days on temperature variation of 0.25N normality and sample was fully
immersed in solution HCL of different normality. The total corrosion rate % of specimen (1) in 0.25N on 30°temperatures
in 36 days is 12.27% and specimen (5) total corrosion rate % in 0.25N on 60° temperatures in 36 days is 16.75% and
specimen (9) total corrosion rate % in 0.25N on 80° temperatures in 36 days is 45.13%. It can be seen that the total
corrosion rate % is increase with the increase in temperature shows in graph. The corrosion behavior of A1 2024 in 0.50 N
normality’s at variation of temperature 30°, 60°, 80° for interval of 6, 12, 18, 24, 30 and 36 days. Effect of temperature
variation in 0.50N normality’s on corrosion rate of A1 2024 in HCL solution shown in figure ll(b). The total corrosion rate
% of specimen (2) in 0.50N on 30°temperatures in 36 days is 15.53% and specimen (6) total corrosion rate % in 0.50N on
60° temperatures in 36 days is 65.70 % and specimen (10) total corrosion rate % in 0.50N on 80° temperatures in 36 days is
75.98%. It can be seen that the total corrosion rate % is increase with the increase in temperature shown in graph. The
corrosion behavior of A1 2024 in 0.75 N normality’s at variation of temperature 30°, 60°, 80°for interval of 6, 12, 18, 24, 30
and 36 days. Effect of temperature variation in 0.75N normality’s on corrosion rate of A1 2024 in HCL solution shown in
Figure ll(c). The total corrosion rate % of specimen (3) in 0.75N on 30°temperatures in 36 days is 24.93% and specimen
(7) total corrosion rate % in 0.75N on 60° temperatures in 36 days is 72.34% and specimen (11) total corrosion rate % in
0.75N on 80° temperatures in 36 days is 85.43%. It can be seen that the total corrosion rate % is increase with the increase
in temperature variation shown in graph. The corrosion behavior of A1 2024 in 1 N normality’s at variation of temperature
30°, 60°,for interval of 6, 12, 18, 24, 30 and 36 days. Effect of temperature variation in 1N normality’s on corrosion rate of
A1 2024 in HCL solution shown in figure ll(d). The total corrosion rate % of specimen (4) in 1N on 30°temperatures in 36
days is 42.16% and specimen (8) total corrosion rate % in 0.75N on 60° temperatures in 36 days is 90.23 %.
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
301
Figure 12(a): 0.25N
Figure 12(b): 0.50N
Figure 12(c): 0.75N Figure 12(d): 1N
In the interval of time 6, 12, 18, to 36 days, the corrosion rate increased gradually due to increase in temperature,
therefore raised in acid concentration. The corrosion behavior of the A1 2024 was due to the constitution of pits cracks on
the surfaces, as absorbed on the sample. It can be seen that higher concentration of HCL ions destroys the passive film of
the surface, which incline to insulate the metal from of corrosive solution. A similar pattern absorbed in corrosion rate of A1
2024 on different normality, whereas with increased temperature, the corrosion rate was seen as shown in the graph.
Combined Results for Temperature and Normality Variation
The weight loss results and corrosion rates for A1 2024 corrosion in 0.25N, 0.50N, 0.75N, and 1N HCL acid
solution with temperature at 30°,60° and 80° are shown in Table 2. It was found that increase in either temperature or
concentration of the acid solution led to rise in corrosion rate. As shown in figure 12, as temperature was increased,
corrosion rate also increased because of rise in acid concentration with pH 1.
Table 3: Values of A12024 Weight Loss and Corrosion Rate at different
Concentrations of (HCL) at different Temperatures
Temp(C)
30°C
60°C
80°C
Conc. (N)
Wt. Loss (g)
Corrosion Rate
(mm/py)
Wt. Loss
(g>
Corrosion
Rate(mm/py)
Wt. Loss
(g)
Corrosion
Rate (mm/py)
0.25N
1.6217
7.2274
2.4611
10.775
6.1169
26.8239
0.50N
2.5771
9.3502
8.4409
38.5152
11.4430
48.2095
0.75N
3.2359
14.5576
11.1359
46.8075
14.7302
67.2927
1N
4.9812
23.3505
13.3455
59.8761
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Q.
o
70
60
50
40
30
20
10
0
■ 60-70
■ 50-60
■ 40-50
■ 30-40
■ 20-30
■ 10-20
■ 0-10
0.25
0.50
60
Teniperaturs
0.75
Normality's
Figure 13: Showing the Variation of Corrosion Rate as a
Function Temperature and Acid Concentration
Measurement of Surface Roughness and Micro-Hardness
The surface roughness of the A1 2024 material is 0.62 to 0.66 microns. Micro-Vickers Hardness of the A1 2024 in
different normality’s 0.25N, 0.50N, 0.75N, 1N on 30° Temperature. Micro-Vickers hardness of base metal is 88HV and
other corrosion sample Micro-Vickers hardness in different normality’s is 0.25N (76HV), 0.25N (81HV), 0.75N (83HV)
and 1N (85HV) shown in the figure 13. In 0.25N, 0.50N, 0.75N and 1N corrosion specimen hardness is decrease due to the
corrosion in 36 days.
m
w
G>
c
■c
I—
ra
6
u
I
86
84
82
80
78
76
74
72
70
0 .
0.50, 81
,76
0.75, 83
T
T
■ Temp 30
0.25 0.50 0.75 1
Normality:s
Figure 14: Showing the Micro-Vickers Hardness of Corrosion Specimen at Different Normality’s
Microstructure
An optical microscope was used to analyze the specimen surface for morphological changes after the full
immersion test of A1 2024. Optical microscope was used to capture images of alloy before and after corrosion. Optical
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under 303
Fully Immersed Condition ofChloride (HCL) Media
micrograph for the same area of A1 2024 specimens shown in figure 14(a), (b), (c), (d) the polished surface as the rolling
direction of the bar, from top to the bottom of the micrograph and figure (e), (f), (g), (h) are showing the same surface after
36 days corrosion in different normality 0.25N (1) specimen, 0.50N (2) specimen, 0.75N (3) specimen, 1N (4) specimen on
30° temperatures. Susceptibility to inter-granular corrosion and localized corrosion depends upon the microstructure of
alloy. Grain boundaries were attacked on surface and large pits developed within the grains. The pits were showed in
crystallographic aspect i.e. tendency to rise following sealed crystal planes can be as curtained in Figure 15a.
Sample 1
Figure 14(a)
Sample 2 Sample 3
(b) (c)
Figure 15: (a), (b), (c), (d) Specimen Sample before Corrosion
Sample 4
(d)
Figure 15: (e), (f), (g), (h) Specimen Sample after Corrosion
SEM & EDS
Electron microscopy has the proficiency that can be used as an electron beam to image a specimen. The smaller
wavelength of electron beam makes it potential to achieve a resolution, importantly better than a light microscope. A beam
of electrons is produced at the top of a scanning electron microscope from thermionic gun or field emission electron gun
during SEM operation, charging and longtime electron hitting may affect the specimen surface condition and image
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quality. The basic principle behind scanning electron microscopy (SEM) is that, a beam of electrons is focused and scanned
across a sample surface and provides high-resolution and increased depth-of-field images of the sample surface. Scanning
electron microscopy (SEM) & Energy dispersive x-ray spectrometry was used to enquire the chemical composition or
morphology of the specimen surface and consistent partials, because, the corrosion behavior of the specimen was found by
the SEM, especially with electron beam at operating voltage at high magnification.
Specimens were firstly analyzed by optical microscopy. Then, an observation by the scanning electron microscopy
SEM was performed with an in order to study the behavior of the localization of pits or inter-granular attack. The energy
dispersed spectrometry EDS analysis were performed during SEM an observation to study the development of the
intermetallic particle composition. SEM images, identical of the alloy surface after 36 days of fully immersion in 0.25N,
0.50 N, 0.75N and 1N on 30° temperatures is shown in figure 15(a). The morphology and chemical composition of the
particles for a specimen after 30 days corrosion test is given. The particle containing A1 -cu-Fe, and Mn was found to
promote the crystallization dissolution leaving slight ditch at the outer boundary. The particles that dissolved, therefore,
appeared to have mostly cu particles left. P and Cr have shown by the peaks in the EDS spectra.
2.5
2.0
1.5
1.0
0.5
0.0
Figure 16(a): SEM Images of Identical Zone and EDS of the A1 2024
Surface after Corrosion 0.25N on 30° Temperatures
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
AppMech 2017/06/20 19:23 F D5.7 xlOO 1 mm
0.5 1.0 1.5 2.0 2.5
keV
0.5 1.0 1.5 2.0 2.5 3.0
keV
Figure 16(b): SEM Images of Identical Zone and EDS of the A1 2024
Surface after Corrosion 0.50N on 30° Temperatures
Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
An Investigation of Localized Corrosion ofAl 2024 under
Fully Immersed Condition ofChloride (HCL) Media
AppMech 2017/06/20 19:39 F D5.6 x250 300 um
keV
Figure 16(c): SEM Images of Identical Zone and EDS of the A12024
Surface after Corrosion 0.50N on 30° Temperatures
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Figure 16(d): SEM Images of Identical Zone and EDS of the A1 2024
Surface after Corrosion 1N on 30° Temperatures
They represent the residuals from chemical cleaning. More important Cu deposition was discovered on the A1 -
Cu - Mn - Fe - containing particles with nodular Cu deposited on those particles, irrespective of their size. The
phenomenon is similar to that of deposition corrosion [16]. Corrosion for long periods of time led to development of
individual pits or cracks in breadth and depth, causing the formation of larger pits through by the coalescence. Accelerated
corrosion damage by the particles- nucleated pitting in the A1 2024.
CONCLUSIONS
The corrosion of AL2024 in acidic chloride (HCL) with pH solution has been investigated by using weight loss
technique over a period of 36 days, in full immersion solution of HCL. The following could be inferred as observed from
the experimental data.
• Increase in temperature of HCL solution led to higher dissolution of chloride ions with rise in temperature and so
decreased corrosion resistance efficiency of A12024.
• The corrosion rate of the A1 2024 was found to be subject on both temperature variation and acid concentration.
AppMech 2017/06/20 19:52 F D4.9 x250 300 um
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
keV
www.tivrc. 0 r 2
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306
Anil Kumar & Vinay Saini
• The weight loss revealed that maximum corrosion rate was found to happen at 1N HCL at temperature 80°C.
• Results obtained showed that in corrosion reaction of AL2024, the corrosion rate was found to increase with
increasing temperature and acid concentration.
• Susceptibility to inter-granular corrosion and localized corrosion depends upon the microstructure of alloy. Grain
boundaries were attacked on surface and large pits developed within the grains.
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Impact Factor (JCC): 6.8765
NAAS Rating: 3.11
