جستجوی مقالات مرتبط با کلیدواژه "electrochemical tests" در نشریات گروه "علوم پایه"

This study investigates the deterioration of water pipes made from two series of copper alloys, Ecobrass 1 (E1) and Ecobrass 2 (E2), when they are buried underground. Buried drinking water pipes often experience significant degradation, leading to a loss of drinking water. This degradation is influenced by climatic conditions, soil type, and the pressure due to depth. This study aims to determine the most suitable alloy for use in buried metal pipelines. The corrosion behaviour of Ecobrass in an aggressive soil environment was investigated using various methods. These included electrochemical impedance spectroscopy, polarization curves, and scanning electron microscopy coupled with an energy dispersive spectrometer (SEM-EDS). Additionally, an analysis was conducted using X-ray diffraction. The findings revealed that E2 had the best corrosion resistance in the aggressive soil with the lowest corrosion current density and the lowest anodic current density. The corrosion products were primarily composed of metal oxides such as Cu2O, CuO, and ZnO, with other compounds like SiO2 also present on the surface of E2. In comparison to E1, E2 demonstrated significantly better corrosion resistance in the Kenitra soil. These results provide compelling evidence to support the selection of E2 as the preferred type of Ecobrass for use in buried pipes.

The corrosion of aluminum beverage cans poses a significant industrial challenge that causes economic and health problems. However, there exists a requirement to gather scientific data that can offer knowledge to the food and packaging sectors, aiding in enhancing materials and reducing losses linked to this issue. This research examined how aluminum cans interacted with beverages using model solutions containing copper and chloride concentrations close to those typically found in beverages. This research highlights the influence of the temperature (20-50 °C), chloride concentration (25-1000 mg/L), and copper concentration (25-1000 µg/L) as independent variables on the corrosion of Al can in citric acid solution using Response surface methodology (RSM) with the Box–Behnken design (BBD). The input corrosion current density was assessed through potentiodynamic polarization tests conducted under variable conditions outlined in the design matrix. With p-values under 0.05 and good regression coefficients (R2), the (ANOVA) approach confirmed that the quadratic model developed was significant.  The RSM demonstrated a strong alignment between the predicted outcomes and the observed responses. The [Cl-] exhibited the most prominent and adverse impact on the dissolution of aluminum. The EIS graphs indicated that the corrosion reaction is primarily governed by the diffusion process.

Characterizing the corrosion behavior of pipeline brasses undergoing cyclic temperature variation is essential for the prevention of degradation. Two brass alloys, (α+β)-brass and α-brass, were studied to evaluate their surfaces in drinking water at constant and cyclically varying temperatures. Both alloys were immersed for 1h in drinking water at nine different temperatures, starting at 278 K, and going up to 318 K. The two copper-zinc alloys were also immersed for 96 h at both critical temperatures (278 K and 318 K) and room temperature. To study the effect of cyclic temperature variation, immersion tests at cyclically varying temperatures were done between the two critical values for 4 cycles. The results of an integral electrochemical analysis using (PDP) and (EIS) revealed that the two alloys react differently under the same experimental conditions. The corrosion rate has approximate values for the cyclical temperature change of 3.04 µA cm-2 for α-brass and 3.26 µA cm-2 for (α+β)-brass. Impedance tests also show that α-brass tends to hold up remarkably well with 130.5 KΩ.cm² of polarization resistance versus 94.1 KΩ.cm² for (α+β)-brass. Similarly, degradation was observed in both alloys during cyclic temperature changes. The etched surfaces of the alloys were examined using SEM-EDX to obtain a clearer understanding of the surface morphology. The SEM images showed that an oxide film protects the surfaces. Monitoring of Cu2+ and Zn2+ ions in the electrolyte by ICP provided a detailed idea of the leaching of these metals.

Inhibitory effect of extracts from three date varieties namely khalt (kha), Lassiane (La) and Tadmamt (Td)), and the mixture of date varieties as environmentally friendly corrosion inhibitor for carbon steel in 1M HCl is studied by means of electrochemical tests such as electrochemical impedance spectroscopy (EIS), and Tafel polarization. It's been obtained that in 1.0 M HCl solution the date extracts are a new green corrosion inhibitor for carbon steel. The results found show that with increasing concentration of the date extracts the values of inhibition efficiency increased. Comparison of the experimental results of the three varieties and the extract mixture of dates, exhibited that inhibition efficiency increased in order Kha, La, Td and the mixture. Therefore, the extract mixture is the best inhibitor with a maximum inhibitory efficacy value reaching 91% at a concentration of 1% of the mixture. Polarization study revealed that dates extracts acted as a mixed inhibitor, with more principally cathodic process. The compounds of the date extracts are adsorbed on the metal surface forming the protective film, which explains the inhibitory action of these extracts, this result is confirmed by electron scanning microscopy (SEM).