Papers by Keyword: Potentiodynamic Polarization

Abstract: This study investigates the effect of nano-TiO₂ (nTiO₂) reinforcement on the corrosion behaviour of cold work aluminium composites in a 0.3M H₂SO₄ environment. Al-nTiO₂ composites were fabricated with 0%, 1%, 2%, 3%, and 5% weight fractions of nano-TiO₂ using stir casting. The corrosion performance was evaluated using potentiodynamic polarization (PDP), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The results show that increased TiO₂ content enhances corrosion resistance up to 5%, particularly at lower cold-working loads. Sample J (5% TiO₂, 2 kg load) exhibited the lowest corrosion rate (0.09474 mm/yr) and highest polarization resistance (809.58 Ω). SEM/EDX analysis revealed denser passive layers and reduced sulfur compound deposits in higher TiO₂ composites. This work highlights the effectiveness of nano-TiO₂ in improving electrochemical stability and corrosion morphology of aluminium composites in acidic environments.

Abstract: Electrochemical analysis of corrosion in molten nitrate salt of stainless steel grade SS 430, SS 2205, SS 2507 and SS 304 is directly performed to evaluate corrosion resistance. Stainless steels are exposed to molten nitrate salt at 600 °C for two hours. This is done in a furnace equipped with a working electrode terminal, reference and counter electrodes. According to this, electrochemical impedance spectroscopy and potentiodynamic polarization techniques are applied in situ to measure corrosion rates and corrosion resistance. Microstructures of stainless steel reveal the ferrite phase for SS 430, the austenite phase for SS 304 and the duplex phase for SS 2205 and SS 2507. In this study, the existence of an austenite phase promotes corrosion resistance in molten nitrate salt.

Abstract: The potentiodynamic polarization method has investigated the corrosion behavior of zinc metal in 3.5% NaOH with a variation of bee wax popolis extract (BWPE) inhibitor, variation of immersion time, and temperature. Zinc plates were tested at 150 °C and 200 °C with immersion durations of 2, 4, and 6 hours, respectively. The variation of inhibitor concentration on corrosion rate has also been studied from 0, 200, 400, 600, 800, and 1000 ppm, followed by testing temperature variations of 25, 35, and 45°C for optimal inhibitor concentration. It is expected that this research will contribute to alternative organic corrosion inhibitors. Tafel polarization test results demonstrated that the corrosion rate of zinc metal in 3% NaOH increased with increasing test temperature and immersion time. Increasing the concentration of BWPE inhibitor from 200 ppm to 1000 ppm can reduce the corrosion rate of zinc metal from the sample without blank with optimal inhibition effectiveness obtained at a concentration of 800 ppm by 46.16%

Abstract: The importance of non harmful inhibitors has informed the application of drugs as an agent to mitigate corrosion of metal materials. This research reveals the inhibitive reaction and adsorption mechanism of Chlorpheniramine drug (CD), on mild steel in an HCl solution using Potentiodynamic polarization, open circuit potential and weight loss method. The CD inhibitor was proportioned into 2.5, 5, 7.5, and 10ml while molarity of HCl was varied in the proportion of 0.1, 0.5, 1.0 and 1.5M at a temperature of 298 K. The reaction showed that as the CD concentration moves to higher concentration, the efficiency of the inhibitor increases, also the higher the concentration of the acid, the higher the corrosion rate. Observation from the result revealed that CD inhibitor protected the steel from corrosion destruction. The optimum efficiency occurred as 85.80% at 10ml CD concentration. CD inhibitor obeyed Freundlich law of isotherm with the average regression value of R² = 0.9733, as R² value gets close to unity. Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectra (EDX) results also confirm strong adsorption mechanisms of CD inhibitor on the mild steel samples. Keywords: Chlorpheniramine Drug; Green Inhibitor; Open circuit potential; Potentiodynamic Polarization; Mild steel

Abstract: In this study, the corrosion behavior of aluminum alloy was investigated in graphene nanoplatelet (GNP) nanofluids prepared with different surfactants. The surfactants include sodium dodecylbenzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), Tween 80, and Gum Arabic (GA). The corrosion properties of the alloy in the different GNP nanofluids were evaluated using potentiodynamic polarization tests at room temperature. The surface morphology of the aluminum alloy was analyzed using a scanning electron microscope coupled with an electron dispersive spectroscopy detector. The experimental results revealed that the addition of surfactants improves the resistance of the aluminum alloy to corrosion in the nanofluid. This was attributed to the adsorption of surfactants on the surface of the alloy to form a protective film layer, which reduces moisture permeability and enhances corrosion inhibition. The addition of GA was found to exhibit the highest inhibition efficiency. This was followed by Tween 80, SDS, and SDBS, which contributes the least inhibition. XRD post-corrosion analysis also reveals the presence of aluminum oxide and aluminum hydroxide phases on the surface of electrodes immersed in all the different GNP nanofluids.

Abstract: This research examined the corrosion inhibition potency of inhibitive Ibuprofen drug (IID)on aluminium 6063. The effect of the inhibitive drug was tested in 0.5 M of H2SO4 solutionusing potentiodynamic method. The concentration of IID was mixed to the acidic mediumin 0, 5, 10, 15 and 20 ml respectively. The polarization experiment shows IID adsorbed onaluminium specimens. Increase in IID concentration decreases corrosion rate of aluminiumspecimens. Maximum inhibitive efficiency of 80.58 % and further studies on the inhibitoryeffect of the drug inhibitor revealed that Freundlich isotherm displayed a regressioncoefficient value of 0.7893 while Langmuir isotherm exhibits a regression coefficient valueof 0.8864. These values of regression establish the reliability of IID as inhibitor, whichshows that IID can be used as inhibitor corrosion of aluminium in aggressive environmentsuch as marine and petrochemical industries where protection of aluminium is a necessity.

Abstract: The external surface of the pipeline steels can be protected from corrosion by cathodic protection and a suitable coating system. But to protect the internal surface of steel pipelines from corrosion is always a challenge. In the current study, a protective aluminum coating was applied on the internal surface of steel pipeline grades API X56 and API X70 by hot dip aluminization process to minimize the cost of inhibitors. The steel substrates were dipped in the hot aluminum bath, whose temperature was maintained at 720 °C, for three different dipping times (5, 7.5 and 10 minutes) and then permitted to cool to room temperature. The coated specimens were characterized in terms of their structure and composition by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM micrographs analysis reveal that the hot dip aluminized specimens gave an unwavering and well adherent interface which is essential for corrosion resistance of the substrates. The corrosion behavior was evaluated by weight loss method in case of sweet corrosion (in 1.0 % NaCl + CO₂ environment) and, by electrochemical potentiodynamic polarization tests for marine corrosion (in 3.5% NaCl environment). The sweet corrosion rates showed severe material loss (14.17 mpy for API X56 and 6.6 mpy in case of API X70) of uncoated samples as compared to the aluminized samples which showed no corrosion at all even after one week due to the passive layer of Al₂O₃. Whereas the marine corrosion of aluminized specimens was also reduced to 0.11 mpy (coated specimens) from 0.57 mpy (uncoated specimens).

Abstract: The influence of surface topography on the corrosion behaviors of DP590 steel was studied by damp heat tests and electrochemical measurements in this paper. Results show that the corrosion behaviors of DP590 steel cannot be evaluated by using average surface roughness (Sa) due to the little difference of surface roughness. Reduced valley depth (Svk) showed a good correlation with corrosion resistance in the potentialdynamic polarization test, and the greater Svk, the better the corrosion resistance. Furthermore, DP590 sample with higher proportion of peak on the surface tended to have more corrosion points during the damp heat test since peaks were electrochemically active.

Abstract: In the present work, samples of a binary intermetallic alloy (Fe₃Al) with 26at.%Al were submitted to electrochemical corrosion evaluation in a 0.5M H₂SO₄ solution containing naturally dissolved oxygen. The corrosion resistance was evaluated by applying linear polarization, electrochemical impedance spectroscopy and potentiodynamic polarization at 22 and 35°C. The results obtained revealed that in both conditions the material exhibits active-passive behavior. Heating to 35°C did not alter the passivity characteristics of the alloy (passivation range and passive current density), but elevated the corrosion current density and the critical current density. The polarization resistance of the samples was also decreased with temperature, following the trend observed for the corrosion current density.

Abstract: Corrosion is the process of natural changes in the nature of a material due to the influence or reaction with the surrounding environment. One way to control it is by adding inhibitors. In this study, seeds from guava (Psidium Guajava) were used as organic inhibitors. The test material used is API 5L grade B steel. For corrosive media, a solution of 1 M H₂SO₄ is used. In experiments used variations in the concentration of extracts 0, 2, 3, 4, 5 and 6 ml. The results of the experiments showed a decrease in the corrosion rate of API 5L grade B when there were additional inhibitors. This is supported by the experimental results of Potentiodynamic Polarization. The rate of corrosion without the presence of an inhibitor shows 75,018 mmpy whereas in the presence of 2,8845 mmpy inhibitors. Based on the calculation, the inhibition efficiency is 96.155%. This is also indicated by the results of the testing of weight loss that has been done. The efficiency shown is 90.130%.