Electrochemical Investigation of Cyproconazole as Corrosion Inhibitor for Copper in Synthetic Seawater

Abstract:

This paper presents the investigation of cyproconazole,namely2-(4-chlorophenyl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl) butan-2-ol,ascorrosion inhibitor for copper in synthetic seawater (3.5% NaCl solution).The inhibition action of cyproconazole on the corrosion of copper was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization.The selective desorption of Cyproconazole from copper surface was also studied by the differential polarization curves.EIS indicates that the inhibition formed an adsorption film on copper surface.The inhibition efficiency increases with increasing concentration.Polarization curves show that Cyproconazole acts as mixed-up inhibitor.

• Periodical: Advanced Materials Research (Volume 763)
• Pages: 23-27
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.763.23
• Online since: September 2013
• Authors: Ji Liu, Li Zheng, Hai Bo Gan, Huan Liu, Zhi Hua Tao, Wei He
• Keywords: Copper, Corrosion, EIS, Polarization Curve, Synthetic Seawater

References

[3] Results and discussion.

[3] 1 Polarization curves Fig. 2 shows the anodic and cathodic potentiodynamic polarization curves for copper in 3. 5% NaCl solution with addition of arious concentrations of synthetic at 293 K. The electrochemical parameters including Ecorr, Icorr, η, anodic and cathodic Tafel slopes (ba, bc) obtained from polarization measurements are listed in Table 1. Tafel slopes of the cathode and anode significantly change with cyproconazole concentration and the corrosion potentialsare found to change, showing that the anodic and the cathodic reactions were affected by the inhibitor [4, 5]. The cathodic reaction of copper in NaCl solution can be described by[6, 7] O2 + 2H2O + 4e →4OH- (1) The process of dissolution of the copper in the anode [6, 7] Cu + Cl- →CuCl + e (2) In Fig. 2 and Table 1, it can be seen that both the cathodic reaction(Eq. (1) and the process of dissolution of the copper(Eq. (2) were delayed, which means the copper electrochemical corrosion is inhibited. The change in the open circuit potential displacement value is less than 85 mV, so cyproconazole compound should be considered as a mixed-type inhibitor [8]. The inhibition efficiency was calculated using [9, 10] η%=Icorr-IinhIcorr×100 (3) where Icorr and Iinh represent the corrosion current density of copper with various concentrations and without inhibitor in 3. 5% NaCl solution, respectively. From Table. 1 it can be seen that the current density in solution using the inhibition has lower values compared with that of the blank solution and the inhibition efficiency increased with the increasing of cyproconazole concentration. Fig. 2 Polarization curves for copper in 3. 5% NaCl solution with different concentrations of inhibitor at 293 K. Table 1 Polarization parameters and corresponding inhibition efficiencies for the corrosion of copper at different concentrations of cyproconazole at 293 K. Concentration (M) Ecorr (mV SCE) Icorr (μAcm-2) bc (mVdec-1) ba (mVdec-1) η% Blank.

[3] 2×10-6.

[1] 0×10-5.

[3] 2×10-5.

[1] 0×10-4.

[3] 2×10-4 -196 -186 -222 -219 -258 -251.

9241.

6304.

4349.

2188.

(2079).

1709 473. 7 177. 4 188. 6 257. 7 143. 8 192. 6.

[57] 5.

[56] 7.

[52] 1.

[53] 8.

[64] 5.

[58] 1.

[31] 78.

[52] 94.

[76] 32.

[77] 50.

[81] 51.

[3] 2 Electrochemical impedance spectroscope Nyquist plots in the presence and absence of different cyproconazole concentration are shown in Fig. 3. It shows that the diameter of arcs increased with cyproconazole concentration, which indicates that the impedance values have increased and corrosion is inhibited. Impedance spectra fitting equivalent circuit diagram is shown in Fig. 3, where Rs is the resistance of the solution between the copper electrode and the reference electrode. Rt stands for charge-transfer resistance. W is the Warburg impedancewhich is attributed to the diffusion of soluble reactant or product species [11]. Q is a constant phase element(CPE) and can be described by the expression: Q=Y0(jω)n (4) where Y0 is the magnitude, j is the imaginary root, ω is the angular frequency, n is the deviation parameter [12]. The impedance data was analyzed and the fit parameters are listed in Table 2. Fig. 3 Nyquist diagrams for copper in 3. 5% NaCl solution with different concentrations and equivalent circuits of the impedance spectra with Warburg impedance. The inhibition efficiency η% with cyproconazole in different concentrations is calculated by [9] η%=Rt-Rt0Rt×100 (5) Rt0 and Rt are the electron transfer resistance in the presence and absence of inhibitor, respectively. Table 2 Impedance parameters of copper in 3. 5% NaCl solution with different concentrations of inhibitor at 293 K. Concentration (mol/L) CPE Rt (KΩ cm2) W×103 (S s0. 5 cm-2) η% Y0(S sncm-2) n Blank.

[3] 2×10-6.

[1] 0×10-5.

[3] 2×10-5.

[1] 0×10-4.

[3] 2×10-4.

[9] 422×10-6.

[6] 463×10-6.

[4] 865×10-6.

[9] 018×10-6.

[1] 603×10-5.

[1] 501×10-6.

77.

77.

80.

73.

72.

83.

[11] 16.

[23] 34.

[28] 63.

[32] 55.

[35] 62.

[75] 65.

337.

131.

119.

091.

059.

047.

[50] 19.

[61] 02.

[65] 71.

[68] 67.

[85] 25 From the Table 2 it can be seen that the electron transfer resistance increase with increasing of inhibition concentration. It indicates the inhibitor modules have adsorbed onto the copper surface and formed a protective film which would isolate copper and corrosion quality [3]. The charge transfer process has been inhibited by the inhibitor. Increased inhibition was shown with increasing cyproconazole concentration reaching 85. 25% at 3. 2×10-4M level. This result is in line with the polarization curve test concluded. 4 Conclusion Cyproconazole is an effective inhibitor for corrosion of copper in synthetic seawater (3. 5% NaCl) at 293K. It can inhibit the copper corrosion by forming the adsorption protective film on metal surface. Polarization curves indicate that cyproconazole acts as a mixed-type inhibition and the anodic and cathodic processes of the corrosion reactions are inhibited. It is obviously that inhibition efficiency increases with increasing inhibitor concentration. 5 Acknowledgments The author gratefully acknowledges the support of National Natural Science Foundation of China [Supported by NSFC (No：61240055)] and Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (KFJJ201211). 6Reference.

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