Wyniki wyszukiwania - BazTech

1

Citric Acid as an Eco-Friendly Inhibitor for the EN AW-2024 Aluminum Alloy Corrosion in Acidic Medium

Kamarska Kalina

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 1

307--311

EN

The paper presents the results from a study on the possibility to use citric acid as an ecological inhibitor of corrosion in aluminum alloy EN AW-2024 in 0.5 М solution of H2SO4. The study has been carried out by using electrochemical techniques, such as open circuit potential and chronoamperometry. The results reveal that the presence of citric acid in the studied acid medium reduces the corrosion degree of the EN AW-2024 aluminum alloy. The inhibition efficiency increases together with increasing the concentration of the citric acid. The study shows that the citric acid can be used as an ecological inhibitor to fight corrosion in a solution of H2SO4.

2

Electrochemical and Quantum Chemical Investigation on Adsorption of Nifedipine as Corrosion Inhibitor at API 5L X-52 Steel / HCl Acid Interface

Ikpi M. E., Abeng F. E.

Archives of Metallurgy and Materials

|

2020

|

Vol. 65, iss. 1

125--131

EN

Nifedipine, a pyridine derivative was investigated as corrosion inhibitor for API 5L X-52 steel in 2 M HCl solution by potentiodynamic polarization, electrochemical impedance spectroscopy and quantum chemical calculations. Statistical tools were used to compare results of the experimental methods. The results showed that nifedipine is capable of inhibiting the corrosion of API 5L X-52 steel in 2 M HCl solution. Potentiodynamic polarization results reveal that nifedipine functions as a mixed-type inhibitor and presents an inhibition efficiency of about 78% at 500 ppm. Impedance data reveal an increasing charge transfer resistance with increasing inhibitor concentration and also shows comparable inhibition efficiency of about 89-94% at 500 ppm. Thermodynamic parameters imply that nifedipine is adsorbed on the steel surface by a physiochemical process and obeys Langmuir adsorption isotherm. The calculated molecular properties namely the highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, chemical hardness, energy gap, dipole moment, electronegativity and global nucleophilicity index all show a positive relationship to the observed corrosion inhibition efficiency.

3

Corrosion Inhibition of API 5L X52 Carbon Steel by 1-Ethyl-3-methylimidazolium-methanesulphonate and 1-Ethyl-3-methylimidazolium Acetate Ionic Liquids in Hydrochloric Acid

Ikpi Magdalene Edet, Obono Okama Ebri

Archives of Metallurgy and Materials

|

2020

|

Vol. 65, iss. 1

295--304

EN

The corrosion inhibition behaviour of 1-Ethyl-3-methylimidazolium-methanesulphonate (EMIM[MS]) and 1-Ethyl-3-methylimidazolium acetate (EMIM[Ac]) on API 5LX-52 carbon steel in 2 M HCl was investigated using weight loss, potentiodynamic polarization and electrochemical impedance methods. The corrosion rates of carbon steel decreased in the presence of these ionic liquids. The inhibition efficiencies of the compounds increased with concentration and showed a marginal decrease with a 10°C increase in temperature. Polarization studies showed the compounds to be mixed type inhibitors with stronger anodic character. The adsorption mechanism of both compounds on the metal surface was via physical adsorption and the process obeyed the El-Awardy kinetic-thermodynamic model. The associated activation energy of corrosion and other thermodynamic parameters were calculated to elaborate on the thermodynamics and mechanism of the corrosion inhibition process. EMIM[MS] was found to inhibit the corrosion of carbon steel better than EMIM[Ac] and is attributed to the presence of the highly electronegative sulphur atom in its structure and its larger molecular size.

4

Sodium molybdate as the corrosion inhibitor of aluminium alloys in the acidic solution

Kwolek P., Sieniawski J.

Ochrona przed Korozją

|

2018

|

nr 4

86--89

EN

The influence of the initial concentration of sodium molybdate on the mechanism of corrosion of the unalloyed aluminium (1050) and Al2Cu phase in 0.5 M H3PO4 was studied. Sodium molybdate is a promising alternative for chromate-containing corrosion inhibitor of aluminium alloys in the acidic media. In the studied solutions, molybdic blue species are formed. They are efficient inhibitors of corrosion of unalloyed aluminium in the acidic solution. Inhibition efficiency equals to 97%. Al2Cu phase in the acidic solution undergoes selective corrosion. Aluminium is leached, the porous copper structure remains on the surface. Sodium molybdate prevents from this process only temporarily.

PL

Określono wpływ stężenia początkowego molibdenianu sodu na mechanizm procesu korozji aluminium o czystości technicznej (EN-AW 1050) i fazy międzymetalicznej Al2Cu w wodnym roztworze H3PO4 o stężeniu 0,5 mol∙dm−3 . Molibdenian sodu jest potencjalnym zamiennikiem dla chromianów, - inhibitorów korozji stopów aluminium w środowisku kwaśnym. Stwierdzono, że w badanych roztworach wytwarzane są aniony błękitu molibdenowego – jest skutecznym inhibitorem korozji aluminium. Określono stopień ochrony przed korozją - 97%. Faza Al2Cu ulega korozji selektywnej w roztworze kwaśnym. Atomy glinu przechodzą do roztworu – warstwa wierzchnia elektrody zostaje wzbogacona w miedź i jest porowatą. Ustalono, że molibdenian sodu chroni fazę Al2Cu przed procesem korozji selektywnej tylko przez krótki czas.

5

Study on Inhibition of N80 Carbon Steel in 0.5M KCl Solution Saturated with CO2 by Gum Arabic

Palumbo G., Banaś J.

Journal of Casting & Materials Engineering

|

2018

|

Vol. 2, no. 1

5--8

EN

The effect of Gum Arabic (GA) on the corrosion of an N80 carbon steel pipeline in a CO2 -saturated chloride (0.5M KCl) solution was investigated through AC impedance and polarization curves. Potentiodynamic measurements showed that the corrosion current density decreased in the presence of inhibitors and that the inhibitor acts like a mixed-type inhibitor, with anodic predominance. The Nyquist diagrams showed an increase in polarization resistance values in the presence of the inhibitor, thus increasing inhibition efficiency. At higher temperatures, the inhibition efficiency decreased, implying that the inhibition action of GA occurred via the physical adsorption process. The activation parameters of the corrosion process such as activation energies, Ea, and the heat of adsorption, Qads, were calculated, respectively, by the obtained corrosion rate and inhibition efficiency at different temperatures. At higher temperatures, the increase in activation energy combined with the negative levels of the heat of adsorption further supported the physical adsorption nature of the process.

6

Corrosion and Corrosion Protection of Aluminum in Hydrochloric Acid by Using Piperidine

El-Meleigy A. E., Youssef G. I., El-Shayeb H.A., El-Shamy A. M.

Ochrona przed Korozją

|

2014

|

nr 3

66--71

EN

The corrosion and corrosion inhibition of aluminum in different concentrations of HCl solutions in the absence and presence of piperidine was investigated using weight loss method and thermometric technique which complemented with surface examination using scanning electron microscopy (SEM). It has been found that piperidine acts as a good corrosion inhibitor for aluminum and the action depends on the concentration of both acid and inhibitor. The concentration of 2.25 M HCl was chosen to carry out the tests of additives either separately or in pairs. Results for weight loss and thermometric measurement indicated that inhibition efficiency increases with increasing inhibitor concentration. It was found that adsorption of piperidine on aluminum surface follows Langmuir adsorption isotherm with a spontaneous process. On the other hand, addition of increasing amounts of NaNO3 to 2.25 M HCl showing that, at lower nitrate concentration there are a decrease in the induction period which is accompany by a rise in the maximum temperature Tm. While at higher ones C > 0.1, an increase in the induction period is manifested. The high dissolution rates of metals in acidic NO3 solution are the result of an autocatalytic process involving the partial reduction of the NO3 – ion to NO2 .

PL

Korozję aluminium wystawionego na działanie różnych stężeń roztworu HCl oraz inhibitowanie korozji dzięki obecności piperydyny analizowano, badając utratę masy metalu i stosując metodę termometryczną uzupełnioną o badania powierzchni za pomocą skaningowego mikroskopu elektronowego (SEM). Stwierdzono, że piperydyna działa jako skuteczny inhibitor korozji aluminium, a jej działanie zależy od stężenia kwasu i inhibitora. Dodatki badano osobno lub w parach w roztworze 2,25 M HCl. Wyniki pomiarów termometrycznych i wartości utraty masy wskazują, że skuteczność inhibicji zwiększa się wraz ze wzrostem stężenia inhibitora. Stwierdzono ponadto, że adsorpcja piperydyny na powierzchni aluminium ma charakter spontaniczny i przebiega wzdłuż izotermy adsorpcji Langmuira. Z drugiej strony, dodawanie coraz to większych ilości NaNO3 do roztworu 2,25M HCl wykazało, że przy niższych stężeniach azotanównastępuje zmniejszenie okresu indukcji, któremu towarzyszy wzrost maksymalnej temperatury Tm. Natomiast przy wyższych stężeniach C > 0,1, następuje wzrost okresu indukcji. Szybkie tempo roztwarzania metalu w kwaśnym roztworze NO3 jest wynikiem autokatalitycznego procesu obejmującego częściową redukcję jonów NO3 – do NO2 .

7

Inhibition Effect of Nitrogen Containing Ligands on Corrosion of Aluminium in Acid Media with and with out KCl

Sethi T., Chaturvedi A., Upadhyay R. K., Mathur S. P.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 3

591-598

EN

Mass loss and thermometric methods have been used to study the corrosion inhibition of aluminium in HCl solution by nitrogen containing ligands viz. N-(4-N,N-dimethyl - aminobenzal)-p-anisidine (SB1), N-(4-N,N-dimethylaminobenzal)-p-toluidine (SB2) and N-(4-N,N-dimethylaminobenzal)-2,4-dinitroaniline (SB3). Results of inhibition efficiencies obtained from these two methods are in good agreement and have been found to be dependent upon the concentration of inhibitors as well as concentration of acids. Inhibition efficiency of synthesized ligands has also been studied in the presence of KCl with inhibitors.