Basrah Journal of Science (A)
Vol.30(2),142-148, 2012
Potassium Chromate as a Corrosion Inhibitors
for Carbon Steel Alloy In HCl Media
Seif Mohammad Meshari
Department of Physics / College of Science/ University of Basra
E-mail: [email protected]
Abstract:
Potassium Chromate was used as corrosion inhibitors for carbon steel alloy in (0.1 M) HCl medium.
Varied concentrations of Potassium Chromate was (0.001M), (0.002M), (0.003M), (0.004M) and
(0.005M) investigated in study by using the weight loss method at interval times (1, 2, 3… 10)
days. From the results we obtain that the K2CrO4 have a good inhibition effect in HCl medium. This
is attributed to a cathodic and anodic inhibitive effects produced by the chromate ions. Also we
obtain that the inhibition effect increases with increasing the inhibitor concentration. It was
calculated that the optimum concentration of potassium chromate in HCl medium that give the
optimum corrosion inhibition of carbon steel is (0.003M).Inhibition efficiency was calculated for
potassium chromate which reached to (97.63%).
Keywords: Inhibitors, Corrosion, Potassium Chromate.
Introduction:
2007). Mild and carbon steel is a major
Corrosion of metals is a major industrial
utilized in most structural shape such as
problem
beams, plates, bars and pipes which used in
that
has
attracted
a
lot
of
investigations in recent years (Afolabi 2007,
industrial
Aramide 2009). Most metals are inherently
methods for prevention or reduction the effect
unstable and have the natural tendency to
of corrosion. The control of corrosion by
react with their environments to obtain lower
maintaining
energy by forming a chemical compound in a
chemical
more stable state (Wright 2005, Afolabi
inhibitors control (Limaye, et al. 2000,
142
institutes.
There
are
relatively small
additives
refers
various
amount
to
of
corrosion
Potassium Chromate as …..
Seif Mohammad Meshari
Lashari 1996). Corrosion inhibitors retard the
aggressiveness (Bardal and Drugli 2004,
destruction
Amin, et al. 2008).
of
metals
electrochemical
by
reactions
chemical
with
or
their
Experimental:
environment (Antonijevic and Petrovic 2008,
The carbon steel working plates used in the
Kendig
Several
present work were made of the material
inhibitors have been used to reduce the
obtained in table (1). The plates were cut with
corrosion of metals in aqueous solution.
(3cm) width and (10cm) length. All sample
Inhibitors such as chromate set to study in this
were
work and investigate the synergistic effect of
smoothing their cut edges (Kalaivani, et al.
these inhibitors on carbon steel immersed in
2009, Salih S. Al-Juaid 2007, Graeme Wrigth
HCl media.
2005). Each sample was weighted by
According to corrosion inhibitors mechanism
electronic balance for 6th digits before and
the effect of corrosion inhibitors is either due
after immersed in corroded media (0.1 M) Of
to the interaction between components of
HCl. The immersing was at different interval
inhibitors composition and the metal surface
time and different concentration of inhibitors
or due to interaction between the inhibitor and
in corroded solutions. The percentage of
one of the ions present in the aqueous solution
Potassium Chromates in corrosive media was
(Levans 1977, Etzold, et al.1999, kendig and
(0M),
Buchhet 2003). It is well established that
(0.004M) and (0.005M) respectively. The
inhibitors function in one or more ways to
sample were left for some times (1,2,……,10)
control corrosion by adsorption of a film onto
days in corrosive media and after this
the surface of corroding material by inducing
removed, washed in water,
the formation of thick corrosion product, or
ethanol, dried and weighted to determine the
by changing the characteristics of the
weight loss (Abdulkibash, et al. 2008,
environment
Kalaivani, et al. 2009, Al-Juaid 2007,
and
Buchheit
of
2003).
resulting
in
reduced
polished
with
(0.001M),
Aramide
emery
paper
(0.002M),
2009,
(0.003M),
cleaned by
Afolabi
Table (1) Spectrometry Analysis Result of the Carbon Steel Sample.
Element
C
P
Cu
Mn
S
Fe
Composition%
0.4
0.035
0.2
1.35
0.24
Balance
143
and
2007).
Basrah Journal of Science (A)
Vol.30(2),142-148, 2012
HCl Media
Sample
Figure (1) Show the sample immersed in HCl media.
Results and discussion:
Potassium Chromates may be acts as cathodic
Figure (2) shown the effect of the corrosive
inhibitors by accelerates the cathodic reaction
media on carbon steel in absence and
which produce some catalytic action leading
presence
of
to evolution of hydrogen instead of reduction
Potassium Chromate as corrosion inhibitor at
of the Chromates ions to the trivalent state
interval time. It is shown that the weight loss
CrO3-3 which absorbs on the surface of the
of carbon steel increase with increasing the
metal and reduce to some intermediate
exposure time to corrosive media until with
valence and tetravalent stateCrO4-4 acts as
presence of the inhibitor(Kendig and Buchhet
mediator between the metal surface and
2003, Aramide 2009). Also as shown in figure
corrosive media as follow (Afolabi 2007).
of
different
concentrations
(3) increasing the concentration of Potassium
Chromate due to decrease the weight loss
CrO4-2+2e = CrO4-4
(1)
CrO4-4+2H2O = CrO4-2+H2+2OH-
(2)
because The Potassium Chromates is known
to be an effective oxidizing anodic inhibitors
which protect the carbon steel from the HCl
corrosive media by making it in passive state
Figure (4) shown the inhibition efficiency at
thus preventing breakdown of the passive
different inhibitors concentrations were found
oxide which can lead to uniform corrosion.
to
144
increase
with
increasing
Potassium
Potassium Chromate as …..
Seif Mohammad Meshari
w 

p %  1  o   100
 w 
Chromates Concentration. We illustrate the
variation of the protection efficiency with the
(3)
concentration of Potassium Chromate where a
value of (P% = 97.63) has been reached. We
Where w and wo are the weight loss of the
can calculate the inhibition efficiency from
carbon steel in the presence and absence of
the following relation (Abulkibash 2007,
the inhibitor respectively.
Kalaivani, et al. 2009).
60
Weight loss(mg)
50
0M
0.001M
0.002M
0.003M
0.004M
0.005M
40
30
20
10
0
0
2
4
6
8
10
Exposure time(day)
Figure(2) Weight loss as a function to exposure time with different concentrations
145
12
Basrah Journal of Science (A)
Vol.30(2),142-148, 2012
60
1day
2days
3days
4days
5days
6days
7days
8days
9days
10days
Weight loss(mg)
50
40
30
20
10
0
0
0.001
0.002
0.003
0.004
0.005
0.006
Inhibitor concentration(M)
Figure(3) Weight loss as function to inhibitor concentration at interval time
120
Inhibition Efficiency %
100
1days
2days
3days
4days
5days
6days
7days
8days
9days
10days
80
60
40
20
0
0
0.001
0.002
0.003
0.004
0.005
0.006
Inhibitor concentration(M)
Figure(4) Inhibition efficiency as a function to inhibitor concentration at interval time
146
Potassium Chromate as …..
Seif Mohammad Meshari
Conclusions:
B. A. Miksic, W. G. Levans, Society of
From this work on Potassium Chromate as
Automotive
Engineers,
corrosion inhibitor on carbon steel in chloride
Automotive
Engineering,
media we can get the following:
Exposition, Cobo Hall, Detroit, 1977.
International
Congress
and
E. Bardal, J. M. Drugli, Encyclopedia of Life
1- The corrosion rate of carbon steel is
Support Systems (EOLSS), pp.1134, 2004.
increase with increasing the exposure
Fatai Olufemi Aramide, Leonardo Journal of
time to the corrosive media with
Sciences, 15, pp. 47-52, 2009.
absence or presence of the inhibitor.
Graeme Wright, J-Corrosion protection, 26,
2- The corrosion rate of carbon steel is
decrease
with
increasing
pp. 67-77, 2005.
the
M. M. Antonijevic and M. B. Petrovic, Int. J.
concentration of Potassium Chromate
Electrochem.
as inhibitor.
Mohammed A. Amin, Hamdy H. Hassan,
3- Potassium Chromate can be effects as
concentration
of
increasing
the
pp.
1-28,
2008.
Appl Electrochem, 38, pp.1589–1598, 2008.
4- The inhibition efficiency was found to
with
3,
Omar A. Hazzazi, Mohsen M. Qhatani, J
a cathodic and anodic inhibitor.
increase
Sci.,
M.W. Kendig, R.G. Buchheit, Corrosion, 59,
the
No. 5, pp. 379, 2003.
Potassium
Paul D. Goodwin, Gregory C. Frantz, Jack E.
Chromate and the optimum percentage
Stephens,
M.sc
thesis,
Connecticut
of inhibitor in corrosive media was
Department of Transportation, University of
found (0.003M).
Connecticut, 2000.
R. G. Limaye, R. D. Angal, A. S. Radke,
Indian Concrete Journal, 33, pp. 22-26, 2000.
References:
R. Kalaivani, B. Narayanaswamy, J. A. Selvi,
Abdalla Abulkibash, Mazen Khaled, Bassam
A. J. Amalraj, J. Jeyasundari, S. Rajendran3,
El Ali, and Mohammad Emad, The Arabian
Portugaliae Electrochimica Acta, 27, pp. 177-
Journal for Science and Engineering, Volume
187, 2009.
33, pp. 29-40, (2008).
Salih S. Al-Juaid, Portugaliae Electrochimica
Abdul Nabi Lashari, M.sc thesis, Civil
Acta, 25, pp. 363-373, 2007.
Engineering, KING FAHD UNIVERSITY
U. Etzold, K.P. Mohr, P. Hulser, Int. J.
OF PETROLEUM & MINERALS, 1996.
Electrochem. Sci., 17, pp. 20-35, 2010.
Ayo Samuel Afolabi, Leonardo Electronic
Journal of Practices and Technologies, 11, pp.
143-154, 2007.
147
‫)‪Basrah Journal of Science (A‬‬
‫‪Vol.30(2),142-148, 2012‬‬
‫استخدام كروهاث البىتاسٍىم كوثبط للتاكل على سبٍكت الكاربىى‬
‫ستٍل فً وسط حاهض الهٍدروكلىرٌك‬
‫سٍف هحود هشاري‬
‫قسن الفٍزٌاء ‪/‬كلٍت العلىم‪/‬جاهعت البصرة‬
‫الخالصت‬
‫حى فً هزا انبحث اسخخذاو كشوياث انبوحاسٍوو كًثبط نهخاكم عهى سبٍكت انفوالر انكاسبوًَ فً يحهول حايضً يٍ ( ‪ )0.1M‬يٍ‬
‫حايض ‪ .HCl‬حى اسخخذاو حشاكٍض يخخهفت يٍ كشوياث انبوحاسٍوو فً انًحهول و نفخشاث صيٍُت يخخهفت‪ .‬باسخخذاو طشٌقت انفقذاٌ‬
‫بانوصٌ حى حساب يقذاس انخاكم فً انًعذٌ خالل انفخشاث يٍ (‬
‫‪ٌ )1,2,3…….,10‬وو‪ .‬يٍ خالل انُخائج حبٍٍ باٌ كشوياث‬
‫انبوحاسٍوو ‪ K2CrO4‬نه حأثٍش كبٍش جذاً عهى عًهٍت انخاكم فً يحهول‬
‫‪ .HCl‬اٌ هزا انخأثٍش ٌعود انى انخأثٍش انكاثودي و انخأثٍش‬
‫االَودي ألٌوَاث انكشوياث فً عًهٍت انخثبٍط نًعذل انخاكم‪ .‬كًا حبٍٍ اٌ عًهٍت انخثبٍط حضداد بضٌادة حشكٍض اٌوَاث انًادة انًثبطت‪.‬‬
‫اٌضًا حى حساب افضم حشكٍض نهًادة انًثبطت فً يحهول ‪ HCl‬عهى سبٍكت انكاسبوٌ سخٍم وانخً هً بحذود ( ‪ .)0.003M‬باالضافت‬
‫انى رانك حى حساب كفائت انخثبٍط نكشوياث انبوحاسٍوو وانخً وصهج انى )‪.(97.63%‬‬
‫‪148‬‬