Organic inhibitors usually form a barrier film on the metal surface. Organic/inorganic are two primary groups of inhibitors according to their chemical structure 8. The efficiency of the inhibitors and their inhibition mechanism pertains to several parameters (such as corrosive ions, the chemical structure of inhibitors, the number of absorbed sites on the met-surface, etc.) 7. Among these, inhibitors have gained more heed today because of their ease of use and low cost. Various methods are proposed to minimize this problem, such as anodic/cathodic prevention, the use of anti-corrosion coatings, and the application of inhibitors 4, 5, 6. The low resistance of St-12 type steel, a famous industrial grade alloy, against corrosion is one of the challenging dilemmas in its application 1, 2, 3. This claim has been proven by SEM/EDS, contact angel, FT-IR, and XRD analysis. This improvement in the steel performance against corrosion in the presence of an equal ratio of Ce(NO 3) 3 and TSP is the outcome of the formation of a hydrophobic dense film (consisting of Ce(OH) 3, Ce/Fe-phosphate complexes) on the metal surface.
Also, by adding 500Ce-500TPS to the solution, i corr and R ct of steel decreased by about 80% and increased approximately 4-fold, respectively. Corrosion studies (EIS and polarization) have revealed that when 500 ppm of Ce(NO 3) 3 and 500 ppm of TSP are added to the 3.5 wt.% NaCl medium, the highest synergism index (1.27) and inhibition efficiency (73.7%) are achieved. Surface studies were done by SEM, Raman, GIXRD, and EDS methods. The corrosion measurements were conducted in the 3.5 wt.% NaCl environment by EIS and polarization methods. In this study, cerium(III) nitrate and tri-sodium phosphate (TSP) was used as organic and inorganic inhibitors to control the corrosion of steel in a 3.5 wt.% NaCl environment. The synergistic effect of these inhibitors has shown promising results in reducing steel corrosion. One of the ways that have been proposed is the use of organic and inorganic inhibitors, simultaneously. There have been many studies on boosting these inhibitors’ performance in such environments (especially Cl − containing media). These inhibitors do not show very good inhibition properties in saline (NaCl) environments. Since #"Ca"# is not an alkali metal, the compound #"Ca"_3"(PO"_4)_2"# is insoluble in water and will precipitate out of solution as a solid.One application of organic compounds is to utilize them as corrosion inhibitors in acidic environments to diminish steel corrosion. Most #"PO"_4"^(3-)# compounds are insoluble in water, with exceptions being the alkali metals (group 1 on the periodic table), and the ammonium cation, #"NH"_4"#. It's listed under Insoluble Ionic Compounds. Therefore, #"NaCl"# is not one of the exceptions, so it is soluble in water, and is not the precipitate.
If you look at the Soluble Ionic Compounds, most #"Cl"^(-)# compounds, with a few exceptions, are soluble in water. Notice that you first look at the anions, and then the exceptions involving cations. You can determine which is the precipitate by using a list or table of solubility rules, such as the one below. One of the two products is a precipitate because it is insoluble in water. The cations in the above reaction are the sodium and calcium ions, #"Na"^+"# and #"Ca"^(2+)#. These reactions can also form an insoluble gas that bubbles out of solution, or water in a neutralization reaction.
The products of this reaction can be predicted because this is a double replacement reaction, also called a double displacement, and if a precipitate forms, a metathesis.
0 kommentar(er)
