Corrosion Inhibitors: Effect on Aluminum Alloys

Author(s):  
Feyisayo Victoria Adams ◽  
Mbali Mokgatla ◽  
Abubakar Ishak ◽  
Chukwuma Valentine Onwujiuba ◽  
Pwafureino Reuel Moses ◽  
...  

Aluminum alloys are less corrosion resistance compared to the pure aluminum. The less corrosion resistance of the aluminum alloys results from trading their mechanical strength and stability with their corrosion resistance. Aluminum alloys show inhibition in alkaline, acidic, neutral chloride free, and chloride media. This study covers studies done on different inhibitors used in corrosion inhibition of aluminum alloys in various media. Generally, the inhibition efficiency of the inhibitors increases with increase in the concentration of the inhibitors. The inhibition efficiency also depends on the characteristic of the inhibitor; whether it is a mixed-type, anodic, or cathodic inhibitor. The experimental data fit in Langmuir adsorption isotherm indicates physical adsorption, while Gibb’s free energy values show that aluminum alloys’ corrosion inhibition is by spontaneous adsorption process. The addition of chloride in alkaline solution improves corrosion inhibition of aluminum alloys.

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Mahmoud Abbas Ibraheem ◽  
Abd El Aziz El Sayed Fouda ◽  
Mohamed Talaat Rashad ◽  
Fawzy Nagy Sabbahy

Corrosion inhibition and adsorption behavior of two triazole derivatives on API 5L-B carbon steel in CO2-saturated 3.5% NaCl solutions was investigated using potentiodynamic polarization, EIS, and EFM techniques. Specimen surfaces were characterized using SEM, EDX, and XRD. Results show that the two compounds are mixed-type inhibitors and inhibition efficiency increases with increasing concentrations. Adsorption of the two compounds chemisorption and obeys Langmuir adsorption isotherm. Activation energy and thermodynamic parameters were calculated. Surface analyses confirm the formation of iron nitrides on the metal surface which supports results obtained from previous techniques.


Author(s):  
Lebe A. Nnanna ◽  
Kings O. Uchendu ◽  
Glory Ikwuagwu ◽  
Wisdom O. John ◽  
Uche Ihekoronye

Gravimetric technique was used to study the inhibition of aluminium alloy AA8011 in an alkaline medium using an eco-friendly inhibitor, Palisota hirsute. The study revealed that the extract reduced the corrosion rate of aluminium AA8011 from 0.407 mm/yr to as low as 0.106 mm/yr in 0.25 M KOH after being exposed for five hours. The inhibition efficiency was found to increase as the concentration of the plant extract in the medium increased. The adsorption studies, computed from the experimental data revealed Langmuir isotherm as the best model for the isotherm (r2=0.999) on the mild steel surface. Gibb’s free energy of adsorption was also calculated and gotten to be 15.61 kJmol-1, suggesting that inhibitor molecules have been spontaneously adsorbed onto the aluminum surface through physical adsorption mechanism.


2016 ◽  
Vol 13 (2) ◽  
pp. 101-105
Author(s):  
Monikandon Sukumaran ◽  
Kesavan Devarayan

Steel corrosion inhibition in acidic and alkaline medium by ethanolic extract of Milletia pinnata is described in this study. The inhibitive behavior of the inhibitor is evaluated by weight loss measurements, adsorption isotherms, and thermochemical parameters. The inhibitor exhibited a maximum of 87% and 90.5% inhibition efficiency against steel corrosion in 0.5 M NaOH and 1.0 M H2SO4, respectively. The weight loss linearly fit to Langmuir adsorption isotherm with correlation coefficient value close to unity. The thermochemical parameters indicated for predominant physical adsorption of the inhibitor molecules on the steel surface.


Author(s):  
B U Ugi

The corrosion inhibition performance of ethanol extract of Andrographis paniculata (King Bitter) root (EEAPR) on the corrosion of Mild Steel (MS) in 1.0 M HCl and H2SO4 acid solutions at 303K and elevated temperatures of 313, 323 and 333K was investigated and compared. The experimental work was performed by the use of weight loss and hydrogen evolution techniques. The results indicate that the extract inhibit the corrosion of mild steel in both acid media. However, the EEAPR exhibits higher maximum inhibition efficiency of 98.9 % in HCl than in H2SO4 (95.0 %) at 5.0 g/L. Inhibition efficiency was found to increase with increasing concentration of extract in both acid media but decreased with rise in temperature. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of extract on the MS sample in both acid media was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters.Â


2011 ◽  
Vol 8 (2) ◽  
pp. 671-679 ◽  
Author(s):  
D. Nalini ◽  
R. Rajalakshmi ◽  
S. Subhashini

A heterocyclic imidazoline, 3,4,5-trimethoxyphenyl-2-imidazolines (TMP2I) was tested for its corrosion inhibition in 0.5 M H2SO4and 1 M HCl using weight loss, Tafel polarisation and electrochemical impedance techniques. The results show that the inhibition efficiency increases with the increase in concentration of TMP2I and the higher efficiency of about 98% is obtained in both the acid media at 20 ppm. The adsorption of TMP2I obeys Langmuir adsorption isotherm and occurs spontaneously. Cathodic and anodic polarization curves of mild steel in the presence of different concentrations of TMP2I at 300C reveal that it is a mixed type of inhibitor. Electrochemical impedance studies reveal that the system follows mixed mode of inhibition. The surface morphology of the mild steel specimens was evaluated using SEM images


2014 ◽  
Vol 43 (5) ◽  
pp. 299-313 ◽  
Author(s):  
S.A. Umoren ◽  
U.M. Eduok ◽  
M.M. Solomon

Purpose – The purpose of this paper is to investigate the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and blended formulations on the corrosion inhibition of aluminium in HCl solutions at 30-60°C and to study the mechanism of action. Design/methodology/approach – The inhibitive effect of the homopolymers and polymer blend was assessed using weight loss and hydrogen evolution methods at 30 and 60°C. The morphology of the corroding aluminium surface without and with the additives was visualized using atomic force microscopy. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption. Findings – Results obtained show that inhibition efficiency (η%) increases with increase in concentration of the polymers but decreases with increase in temperature. The inhibition efficiency of the homopolymers and their blends decreased with rise in temperature. Inhibition efficiency was found to be synergistically enhanced on blending the two homopolymers with highest inhibition efficiency obtained for (PEG:PVP) blending ratio of 1:3. The phenomenon of physical adsorption is proposed from the trend of inhibition efficiency with temperature. Research limitations/implications – The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as potentiodynamic polarization and electrochemical impedance spectroscopy. Originality/value – Studies involving the use of polymer blends/mixtures as corrosion inhibitor for metals in corrosive environments are scarce. The results suggest that the mixture could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the use of polymer–polymer mixtures to control acid-induced corrosion of metal.


Author(s):  
Omotola M. Fayomi ◽  
Habibat F. Chahul ◽  
David C. Ike ◽  
Gloria I. Ndukwe ◽  
Ikpum M. Phoebe

The study reports the corrosion inhibition activity of methanol extract of Aframomum chrysanthum on mild steel in 0.1 M HCl, using gravimetry analysis. The weight loss of the mild steels was observed to increase with increasing immersion time. The inhibition efficiency (%IE) was also observed to have increased with increasing concentrations of the inhibitor but decreases with increasing immersion time. The effect of temperature change on the inhibition efficiency was also studied and it was observed that for every increase in temperature there was a corresponding increase in weight loss and decreased in the %IE. The highest values of %IE; 46.66, 56.66, 60.0, 80.0 & 93.33 was observed at temperature 303 K for 0.2, 0.4, 0.6, 0.8 & 1.0 g/L respectively. Activation energy (Ea) values and the enthalpy values reviews that the adsorption process followed a physisorption’s mechanism. Change in enthalpy (ΔH) and entropy change (ΔS) of the reaction was positive indicating the endothermic nature and the spontaneity of the reaction. Three adsorption isotherms were tried on the inhibition process and only the Temkin isotherm gave the best fit with R2 value of 0.903, describing the best adsorption mechanism. The adsorption equilibrium constants K­ads were positive, indicating the feasibility of the adsorption of the inhibitor to the metal surface. Gibb’s Free Energy change of adsorption, ΔGads are negative indicating that the adsorption of the extract of Aframomum chrysanthum on mild steel surface is spontaneous. The values of ΔGads shows physisorption mechanism. All confirming that Aframomumm chrysanthum extract is a good corrosion inhibitor on mild steel in 0.1 M HCl.


Author(s):  
N’guessan Yao Silvère Diki ◽  
Nagnonta Hippolyte Coulibaly ◽  
Kadjo François Kassi ◽  
Albert Trokourey

The corrosion inhibition of mild steel by 7-(ethylthiobenzimidazolyl) theophylline (7-ETBT) in 1 M HCl medium was investigated through weight loss and Tafel polarization techniques within a temperature range of 298 to 318 K. The inhibition efficiency depends on the concen­tration of 7-ETBT and reaction system temperature. The maximum inhibition efficiency values of 90.73 and 87.06 %, respectively, were estimated using both weight loss and Tafel polarization techniques at 298 K. The results suggest spontaneous and predominant physical adsorption of 7-ETBT on the metal surface which obeys Langmuir isotherm model. Furthermore, Tafel polarization method revealed that 7-ETBT is a mixed-type inhibitor. Po­tentiodynamic polarization results are in accordance with weight loss data to a good extent.


RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 35455-35465 ◽  
Author(s):  
Binbin Zhang ◽  
Xia Zhao ◽  
Yantao Li ◽  
Baorong Hou

A facile one-step electrodeposition method was used to fabricate a hierarchical papillae-covered SHPS on an Al substrate with enhanced corrosion resistance (corrosion inhibition efficiency ~99.96%) and lotus-like self-cleaning effect.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 605 ◽  
Author(s):  
Chang-Hsien Hsu

As industrial manufacturing technologies continuously improve, many conventional industrial materials are struggling to meet the needs of today’s industries. Aluminum alloys are currently the most extensively used non-ferrous metal in the industry, whose properties include corrosion resistance, high strength, and high ductility. As a result, they are widely used in many products, such as doors and windows, vehicles, and electronics. Pure aluminum though, is a very soft, silver-white metal, so to increase its strength, aluminum alloy manufacturers add in various chemical elements (such as magnesium, silicon, and zinc) according to international standards, and then adjust the proportions based on customer needs. If the chemical element composition does not meet specification requirements, it will affect the quality of the aluminum alloy product or even delay delivery and subsequently impact the operational performance of the manufacturer. To ensure and increase aluminum alloy quality, this study used a combined Six Sigma quality index (SSQI), Qpc, to develop a multi-characteristic quality analysis model (MCQAM) with five steps for the aluminum alloy industry. A practical example with a manufacturer specializing in producing 6063 aluminum alloys in Taiwan is given to demonstrate the effectiveness and feasibility of this proposed approach. The result shows that the proposed method not only effectively improves the quality of 6063 aluminum alloy, but also enhances its performance and capability (that is, corrosion resistance increases by 17%, strength increases by 8%, and stiffness increases by 3%). Finally, future works are also discussed in this context.


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