|
Document Type |
: |
Article In Journal |
|
Document Title |
: |
On the Pitting Corrosion Behaviour of Pure Al by Halide Ions in Neutral Sulphate Solutions and the Effect of Some Inorganic Inhibitors سلوك التأكل الثقبي للألمنيوم بواسطة أيونات الهاليدات في محاليل كبريتات الصوديوم المتعادلة ودراسة تأثير بعض المثبطات غير العضوية |
|
Subject |
: |
Chemistry |
|
Document Language |
: |
English |
|
Abstract |
: |
The pitting corrosion of pure Al in neutral 0.50 M Na2SO4
solution in the absence and presence of NaCl, NaBr and NaI under the
influence of various experimental variables, including X– ions concentration,
temperature and anodic step potential (Es,a), has been studied
using potentiodynamic and potentiostatic techniques, complemented
with Energy Dispersive X-ray (EDX) examinations of the electrode
surface. Potentiostatic measurements showed that the overall process
can be described by three stages. The first stage corresponds to the
nucleation and growth of a passive oxide layer. The second and the
third stages involving pit nucleation and growth, respectively. Nucleation
of pit takes place after an incubation time (ti). The rate of pit
nucleation (ti
–1) increases with increasing halide concentration, temperature,
and applied potential. The pit growth current density (jpit)
increases linearly with t1/2, indicating that the pit growth can be
described in terms of an instantaneous three dimensional growth under
diffusion control. The effect of Cr2O7
2–, CrO4
2–, WO4
2–, and MoO4
2– as
inorganic inhibitors on the pitting corrosion inhibition of pure Al in
(0.5 M Na2SO4 + 0.2 M NaCl) solution has also been studied. The
presence of these anions results in an increase in the incubation time,
and a decrease in the pit growth current density of Al to an extent
depending on the nature and the concentration of the inorganic
inhibitors. The inhibition efficiency of these inhibitors decreases in the
order: Cr2O7
2– > CrO4
2– > WO4
2– > MoO4
2– |
|
ISSN |
: |
1012-1319 |
|
Journal Name |
: |
Science Journal |
|
Volume |
: |
19 |
|
Issue Number |
: |
1 |
|
Publishing Year |
: |
1428 AH
2007 AD |
|
Number Of Pages |
: |
18 |
|
Article Type |
: |
Article |
|
Added Date |
: |
Sunday, October 11, 2009 |
|
Researchers
| عمر عبدالله هزازي | Omar Abdullah Hazzazi | Researcher | | |
|