Enhancing corrosion resistance of the CaCO3/MgO coating via ultrasound-assisted chemical conversion with addition of ethylenediamine tetra-acetic acid (EDTA) on AZ41 Mg alloy

Simultaneously Regulating Electrochemical Corrosion Behavior and Wettability of Magnesium–Neodymium Alloy by Self-Layered Chemical Conversion Coating

“…The equivalent circuit models for fitting are shown in Figure 11d. Roughly speaking, the larger the |Z| value at the lowest investigated frequency, the stronger the corrosion resistance [26,34]. It can be seen from Figure 11a that when the frequency is close to 0.1 Hz, the |Z| value of the coated sample is much larger than that of the uncoated sample.…”

“…High-resolution XPS spectra are deconvoluted and shown in Figure 5 b–e. The three components with binding energies of 284.8 eV, 286.56 eV, and 290.01 eV are obtained by deconvolution of C 1s in Figure 5 b, which belong to C-C, C-O, and C=O [ 34 , 35 ], respectively. Figure 5 c shows that the peak of the high-resolution spectrum of Mg 1s appears at 1304.51 eV, which can be attributed to Mg 2+ rather than metallic magnesium [ 36 ].…”

“…Figure 11 a exhibits the Bode plots by impedance versus frequency and Figure 11 b shows the Bode plots by phase angle versus frequency, Figure 11 c gives the Nyquist plots. The equivalent circuit models for fitting are shown in Figure 11 d. Roughly speaking, the larger the |Z| value at the lowest investigated frequency, the stronger the corrosion resistance [ 26 , 34 ]. It can be seen from Figure 11 a that when the frequency is close to 0.1 Hz, the |Z| value of the coated sample is much larger than that of the uncoated sample.…”

“…By combining the elemental distribution with the XRD results, it is speculated that the bottom layer marked with a dash line is possible to be Mg(OH) 2 . [34,35], respectively. Figure 5c shows that the peak of the high-resolution spectrum of Mg 1s appears at 1304.51 eV, which can be attributed to Mg 2+ rather than metallic magnesium [36].…”