Effect ofortho-substituted aniline on the corrosion protection of aluminum in 2 mol/L H₂SO₄solution

Abstract

Item Type Article Authors El-Deeb, Mohamed M.; Alshammari, Hamed M.; Abdel-Azeim, Safwat Citation El-Deeb MM, Alshammari HM, Abdel-Azeim S (2017) Effect of ortho-substituted aniline on the corrosion protection of aluminum in 2 mol/L H2SO4 solution. Canadian Journal of Chemistry 95: 612-619. Available: http://dx.

Electrochemical and computational estimations of cephalosporin drugs as eco-friendly and efficient corrosion inhibitors for aluminum in alkaline solution

“…The analyses show that increasing the concentrations of Cefx and Cefz improves the Al surface coverage and hence the inhibition efficiency in the sequence Cefx > Cefz. Due to their adsorption via their hetero-active sites on the Al surface, these drugs produce a barrier protective film that inhibits the active sites for reduction reactions 47 .

Figure 5 Variation of the inhibition efficiencies vs. inhibitor concentrations depending on the potentiodynamic polarization measurements at 293 K.

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“…This behaviour is resulted from increasing R s , R ct1 and R ct2 values with decreasing C dl and CPE values in the presence of the studied drugs compared to the inhibitor free solution. These findings can be explained to the replacement of water molecules by the adsorbed barrier protective insulating layers from Cefx and Cefz on Al surface, which decreasing the local dielectric constant and/or increasing the thickness of the adsorbed barrier protective layer, that impedes the charge transfer reaction through Al/electrolyte interface 47 . The inhibition efficiencies ( η %) are calculated from total charge transfer resistance R T (R T = R ct1 + R ct2 ) and listed in Table 3 using the following equation 48 : where θ is the surface coverage, R T o and R T are total charge transfer resistances in the absence and presence of the studied drugs, respectively.…”

Role of S2− ions on the microstructure change and the pitting behaviour of aluminum in saline solution

“…Moreover, the replacement of the double layer capacitance ( C dl ) in the [ R ( RC )/( RC )] equivalent circuit with constant phase element ( CPE ) and phase shift ( N ) in [ R ( RQ )] equivalent circuit explains the dispersion effect and the degree of heterogeneity resulted from the microscopic roughness of aluminum surface due to pitting corrosion 37–39 . The highest value of N accompanied with smallest value of CPE for aluminum in 3.5 wt% NaCl + 5 ppm Na 2 S solution ( N = 0.56 and CPE = 54.9 µMho) compared to their values in 3.5 wt% NaCl solution ( N = 0.52 and CPE = 66.1 µMho) is calculated from the fitted experimental measurements using Boukamp model 40,41 . This means that, Al/electrolyte interface in 3.5 wt% NaCl + 5 ppm Na 2 S solution behaves as a more ideal capacitive rather than that in 3.5 wt% NaCl, which illustrates the role of the S 2− ions in decreasing the roughness and increasing the homogeneity of the aluminum surface.

Figure 3Electrical equivalent circuit model for aluminum/electrolyte interface in ( a ) 5 ppm Na 2 S solution [R(RC)/(RC)] and ( b ) 3.5 wt% NaCl and 3.5 wt% NaCl + 5 ppm Na 2 S solutions [R(RQ)].

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Evaluation of the nano silica and nano waste materials on the corrosion protection of high strength steel embedded in ultra-high performance concrete

“…Data point out that the presence of two consecutive capacitive semicircles, that have been interpreted to the dielectric properties of the concrete bulk in the high frequency region and to the steel/concrete interface at low frequency region 40 . The diameter of these capacitive loops increases without any change in the shapes of the Nyquist plots in the presence of the studied nano materials, suggesting the mechanism of the corrosion resistance in the absence and presence of these materials is not changed 39 . The increase in the diameters of both two capacitive loops that equivalent to the concrete resistance and charge transfer resistance can be explained to the effect of these materials on the microstructure of the UHPC as discussed before.…”

“…www.nature.com/scientificreports/ Electrochemical impedance spectroscopy. EIS is a non-destructive useful technique which provides a detailed characteristic about Metal/solution and Metal/concrete interface [37][38][39] . Figure 15 represents the Neyquist plots of HSS embedded in UHPC in the absence and presence of NS, NWG, NRHS and NMK in both normal and accelerated conditions at Eocp over the frequency range of 100 kHz to 10 MHz.…”