Inhibitory effect of tungstate, molybdate and nitrite ions on the carbon steel pitting corrosion in alkaline formation water containing Cl− ion

The inhibitive mechanisms of nitrite and molybdate anions on initiation and propagation of pitting corrosion for mild steel in chloride solution

“…Besides, the ratio of Fe 3+ and Fe 2+ is 8.32 in the film, much higher than the value of 0.72 for the airformed film, hence NO 2 − effectively promoted the formation of the [21] reported that in a NaCl solution containing MoO 4 2− anions, the passive film showed a double layer structure: the inner layer was composed largely of ferric oxide/hydroxide and the outer layer was composed mainly of Fe 2 (MoO 4 ) 3 . Deyab et al [13] reported the presence of MoO 2 , MoO 4 2− and MoO 3 in the passive film formed in 0.5 M NaHCO 3 + 0.5 M NaCO 3 + 1.5 M NaCl solution containing MoO 4 2− anions and the peak intensity of MoO 4 2− was stronger than the peak intensity of other species. Therefore, according to the XPS results and previous reports, the result suggests that the passive film formed in Na 2 MoO 4 + NaCl solution may be composed of two components: one is Fe 2 (MoO 4 ) 3 and the other is an oxide composed of Fe and O similar to the air-formed passive film.…”

“…Refaey et al [12] studied the inhibition of localized corrosion of mild steel in chloride solutions by MoO 4 2− anions and reported that the addition of increasing concentration of MoO 4 2− caused a shift of the pitting potential in the positive direction, and the adsorption characteristic of MoO 4 2− anions on the steel surface played a significant role in the inhibition. Deyab et al [13] studied the inhibitory effect of MoO 4 2− anion on pitting corrosion of carbon steel in alkaline formation water containing Cl − and reported that the pit initiation rate decreased and the pitting potential moved to the positive direction upon the addition of MoO 4 2− anions. Saremi et al [14] studied the effects of MoO 4 2− on the corrosion inhibition of mild steel in a simulated cooling water and reported that the inhibition efficiency of MoO 4 2− was increased with increasing both the MoO 4 2− concentration and the water circulation velocity.…”

Effect of microstructure variation on the corrosion behavior of high-strength low-alloy steel in 3.5wt% NaCl solution

“…The presence of chloride ions frequently causes the passive film formed on the metal surface to be broken down [6][7]. Continuous damage of the permanent corrosion product layer facilitates the active dissolution of the substrate metal [8].…”

EIS and adjunct electrical modeling for material selection by evaluating two mild steels for use in super-alkaline mineral processing

“…It is shown that the rate of pit initiation (t -1i) decreases and the pitting potential E pit moves to more positive direction upon the addition of inorganic anions. It was found that pitting inhibition of carbon steel increases in the sequence: [20,41]. Figure 4 shows the precipitates formed on the Ck45 specimen from which four sample/EDS analyses are given in Table 6.…”