A new kind of corrosion inhibitor (LOBI) based on linseed oil has been synthesized. The molecular structure of LOBI was investigated using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectrometer. Its inhibiting behavior on mild steel in 1.0 M HCl was studied by electrochemical potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy and X‐ray photoelectron spectroscopy. Results reveal that LOBI was a good mixed‐type inhibitor. The adsorption of LOBI at 40 °C obeys the Langmuir adsorption isotherm. The N(1s) and S(2p) peaks of XPS measurement indicate that LOBI has been adsorbed onto a Q235 steel surface. The adsorption equilibrium constant, adsorption free energy and activation energy were also calculated, which indicated the adsorption of LOBI was chemisorption.
A rapid and convenient anodization technology with AC power source to obtain the MAO films formed on magnesium alloy AZ91D in phosphate bath (base electrolyte þ Na 3 PO 4 ) with or without aluminate and silicate was studied. The corrosion resistance of the anodic films was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques and the microstructure and composition of films were examined by SEM and XRD. The results show that Na 3 PO 4 can promote the occurrence of sparking during the MAO process, while abundant heat generated by sparking might enhance the formation of the glassy phase of the compound when the electrolyte contains the additives of NaAlO 2 and Na 2 SiO 3 simultaneously. The optimized MAO film is ivory-white smooth by naked eye, while presents porous and microcracks in microscopic scale. The anodic film formed in the alkaline solution with optimized parameters possesses superior corrosion resistance by electrochemical test. The XRD pattern shows that the components of the anodized film consist of MgO, MgAlO 2 , and MgSiO 3 . No oxide crystal with P element can be found.
Anodizing of AZ91D magnesium alloy in the alkaline borate-potassium hydrogen tartrate (PHT) environmental friendly electrolyte was studied. The effect of PHT on the anodizing process and anodic film properties was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), and potentiodynamic polarization. The results showed that the anodizing parameters, surface morphology, thickness, phase structure, and corrosion resistance of the anodic film were strongly dependent on the concentration of PHT. Moreover, the anodizing mechanism of the AZ91D magnesium alloy in the presence of PHT was also studied. That is, by adsorption on the surface of magnesium alloy, PHT decreases the anodizing current density and make the anodizing condition moderate, which is conducive to the performance improvement of the anodic film. Experimental Materials and specimen preparationPrior to PEO treatment, the AZ91D magnesium alloy (chemical composition see Table 1) sheets with a size of 0.50 cm 2 were polished up to 2000 grit, degreased with acetone, and washed with distilled water successively. The power supply was an AC power supply (120 V, 50 Hz) and the duration of the PEO process was 3 min. The anodic electrolyte was composed of 60 g/L NaOH, 25 g/L Na 2 B 4 O 7 , 20 g/L H 3 BO 3 , and 0.0-7.2 g/L of PHT (chemical structure formula see Fig. 1). The temperature of the electrolyte Materials and Corrosion 2014, 65, No. 7
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