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General corrosion rates and inhibition efficiencies (obtained from weight loss measurements) of samples with different surface roughness after immersion for different time in 3 wt. % NaCl solution with various concentrations of inhibitor at 333 K (the scatter band in the Figure was standard deviation). The results exhibited that surface roughness had no effect on corrosion rates of samples in the absence of inhibitor. However, the corrosion rates and inhibition efficiencies for samples with different surface roughness were distinct in solutions with inhibitor. However, when the samples were simultaneously immersed in the solution with 1.22 × 10−5 mol/l inhibitor for 1 h, the inhibition efficiencies for samples with rougher surface and smoother surface were 43.1% and 91.8%, respectively. When the samples with different surface roughness were simultaneously immersed in the solution with 1.22 × 10−4 mol/l inhibitor for 240 h, the rougher samples had a larger corrosion rate, and the inhibition efficiencies for rougher samples and smoother samples were 98.8% and 99.4%, respectively. • Surface roughness had an effect on the corrosion of X70 steel with inhibitor. • Samples with smoother surface showed higher inhibition efficiencies. • Fe-inhibitor complex on the smoother surfaces were more ordered. • Smoother surface with higher EWF was more attractive to react with the inhibitor. Effect of surface roughness on the inhibition behavior of X70 steel corrosion in CO 2 -saturated brine by a thioureido imidozaline inhibitor was investigated. Results showed that samples with different surface roughness had the same corrosion rate/corrosion current density in the absence of inhibitor. However, the inhibition efficiencies for samples with different surface roughness were distinct in the presence of inhibitor, and smoother samples exhibited higher inhibition efficiencies. Smoother surface with a higher electron work function was more attractive to react with the inhibitor molecules and then formed a more protective inhibitor film, compared to rougher surface. [ABSTRACT FROM AUTHOR]

• Effect of Sm microalloying on the corrosion resistance of Mg–8Sn–1Al–1Zn alloy was investigated. • Microalloying with 0.02 wt% Sm resulted in the formation of Al 8 Fe 4 Sm instead of nobler Al 5 Fe 2. • Sm microalloying led to about six times improved corrosion resistance in 0.6 M NaCl solution. • The role of the microstructural changes in enhancing corrosion resistance is discussed. We report that the corrosion resistance of hot-rolled Mg–8Sn–1Al–1Zn alloy was significantly enhanced by Sm microalloying. Corrosion rates, measured after immersion for 72 h in 0.6 M NaCl solution, were found to be 2.7 and 19 mm y−1 for the alloys with and without an addition of 0.02 wt% Sm, respectively. Electrochemical and microstructural analyses revealed that the enhanced corrosion resistance achieved by Sm microalloying is mainly a result of a reduced H 2 evolution rate owing to the presence of Al 8 Fe 4 Sm particles instead of nobler Al 5 Fe 2 particles, which highly accelerate microgalvanic corrosion in the alloy without Sm microalloying. [ABSTRACT FROM AUTHOR]

• Strain mainly concentrated within Mg 2 Si particles and at Al/α(Al-Fe-Cu) interface. • Volta potentials of Mg 2 Si and α(Al-Fe-Cu) decreased slightly in the elastic stage. • Volta potentials of Mg 2 Si and α(Al-Fe-Cu) increased in the plastic stage. • The pitting corrosion resistance was improved under elastic deformation. • The pitting corrosion resistance was degraded under plastic deformation. Micro-galvanic corrosion behaviors between two primary intermetallic particles (Mg 2 Si, α(Al-Fe-Cu)) and the Al matrix were investigated under elastic and plastic deformations in AA7075-T6. Strain localization was mainly concentrated within Mg 2 Si and at the interface of α(Al-Fe-Cu)/Al matrix under deformations. The experimental Volta potential differences between Mg 2 Si, α(Al-Fe-Cu) and Al decreased by 0–16 mV and 2–27 mV in the elastic stage but increased by 0–39 mV and 0–81 mV in the plastic stage, which were consistent with the calculation results. Accordingly, the pitting corrosion resistance was improved under elastic deformation but deteriorated under plastic deformation. [ABSTRACT FROM AUTHOR]

• The corrosion resistance of Mg–3Al–1Zn-based alloys with different Mn and Y content was investigated. • The experimental alloy with trace Mn and Y had Al 8 Mn 4 Y particles instead of typical Al-Mn particles. • The novel alloy showed a four times slower corrosion rate than a commercial AZ31 alloy in a NaCl solution. • Factors influencing the improved corrosion resistance of the novel experimental alloy are discussed. The corrosion resistance of conventional and experimental Mg–3Al–1Zn-based alloys with different Mn and Y content was comparatively investigated. After immersion for 72 h in a 0.6 M NaCl solution at 25 °C, an experimental Mg–3Al–1Zn–0.05Mn–0.03Y alloy exhibited a corrosion rate of 0.91 mm y−1, which is about four times slower than that of a conventional Mg–3Al–1Zn–0.3Mn alloy. Microstructural factors underlying the improved corrosion resistance achieved by the trace additions of Mn and Y are discussed. [ABSTRACT FROM AUTHOR]

• AZ91 + 2.0Ca+0.3Sb + SiC nanocomposites revealed better corrosion resistance than alloy. • SiC nanoparticle additions shifted corrosion potential towards more positive values. • Volta potentials of the alloy and nanocomposites were measured by SKPFM. • Volta potentials of the β-Mg 17 Al 12 and Al 2 Ca phases reduced in the nanocomposites. • XPS analysis of corrosion film revealed the presence of Mg(OH) 2 , MgCO 3 and MgO. The present work investigates the effect of SiC nanoparticle additions on corrosion response of the squeeze-cast AZ91 + 2.0Ca+0.3Sb (wt.%) alloy subjected to immersion, hydrogen evolution, and potentiodynamic polarization scan in a 0.1 M NaCl solution. All the AZ91 + 2.0Ca+0.3Sb + xSiC np (x = 0.5, 1.0, 2.0 (wt.%)) nanocomposites demonstrate a superior corrosion resistance than the alloy, and the nanocomposite reinforced with 2.0SiC np exhibits the highest corrosion resistance. The improved corrosion performance of the nanocomposites is attributed to the decrease in the potential difference between α-Mg and β-Mg 17 Al 12 phases, reduced quantity of β-Mg 17 Al 12 phase, and an increased amount of Al 2 Ca phase following SiC nanoparticles additions. [ABSTRACT FROM AUTHOR]