Synergism between protocatechualdehyde and rare earth cerium(IV) ion on the corrosion of cold rolled steel in hydrochloric acid solution |
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| Authors: | X H Li S D Deng G N Mu H Fu |
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| Affiliation: | 1. Department of Fundamental Courses, Southwest Forestry University, Kunming 650224 (P. R. China);2. Department of Wood Science and Technology, Southwest Forestry University, Kunming 650224 (P. R. China);3. Department of Chemistry, Yunnan University, Kunming 650091 (P. R. China) |
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| Abstract: | The synergism between protocatechualdehyde (PAL, 3,4‐dihydroxy‐benzaldehye) and rare earth cerium(IV) ion (Ce4+) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) solution has been investigated by weight loss and potentiodynamic polarization methods. The results reveal that PAL has a moderate inhibitive effect, while Ce4+ has a poor effect. Incorporation of PAL with Ce4+ improves the inhibition performance significantly, and exhibits synergistic inhibition effect. The adsorption of individual PAL obeys the Temkin adsorption isotherm, and the adsorption of the complex of PAL and Ce4+ accords with the Temkin adsorption isotherm too. The thermodynamic parameters of adsorption heat (ΔH0), adsorption free energy (ΔG0), and adsorption entropy (ΔS0) are calculated and discussed. Polarization curves show that individual PAL acts as a mixed‐type inhibitor, while Ce4+ slightly inhibits the corrosion reaction. The complex of PAL and Ce4+ acts as a mixed‐type inhibitor, which drastically inhibits both anodic and cathodic reactions. Depending on the results, the synergism mechanism is proposed from the viewpoint of adsorption theory. |
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| Keywords: | adsorption cerium(IV) ion cold rolled steel corrosion inhibitor hydrochloric acid protocatechualdehyde synergism |
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