In situ monitoring of the localized corrosion of 304 stainless steel in FeCl 3 solution using a joint electrochemical noise and scanning reference electrode technique

The Synergistic Inhibitions of Tungstate and Molybdate Anions on Pitting Corrosion Initiation for Q235 Carbon Steel in Chloride Solution

In this work, the synergistic inhibitions of tungstate (WO₄^2-) and molybdate (MoO₄^2-) anions, including role and mechanism, on the initiation of pitting corrosion (PC) for Q235 carbon steel in chloride (Cl^-) solution were investigated with electrochemical and surface techniques. The pitting potential (E_p) of the Q235 carbon steel in WO₄^2- + MoO₄^2- + Cl^- solution was more positive than that in WO₄^2- + Cl^- or MoO₄^2- + Cl^- solution; at each E_p, both peak potential and affected region of active pitting sites in WO₄^2- + MoO₄^2- + Cl^- solution were smaller than those in WO₄^2- + Cl^- or MoO₄^2- + Cl^- solution. WO₄^2- and MoO₄^2- showed a synergistic role to inhibit the PC initiation of the Q235 carbon steel in Cl^- solution, whose mechanism was mainly attributed to the influences of two anions on passive film. Besides iron oxides and iron hydroxides, the passive film of the Q235 carbon steel formed in WO₄^2- + Cl^-, MoO₄^2- + Cl^-, or WO₄^2- + MoO₄^2- + Cl^- solution was also composed of FeWO₄ plus Fe₂(WO₄)₃, Fe₂(MoO₄)₃, or Fe₂(WO₄)₃ plus Fe₂(MoO₄)₃, respectively. The film resistance and the defect quantity for Fe₂(WO₄)₃ plus Fe₂(MoO₄)₃ film were larger and smaller than those for FeWO₄ plus Fe₂(WO₄)₃ film and Fe₂(MoO₄)₃ film, respectively; for the inhibition of PC initiation, Fe₂(WO₄)₃ plus Fe₂(MoO₄)₃ film provided better corrosion resistance to Q235 carbon steel than FeWO₄ plus Fe₂(WO₄)₃ film and Fe₂(MoO₄)₃ film did.

Polymer Nanocomposite-based Coatings for Corrosion Protection

Corrosion of metals induces enormous loss of material performance and increase of cost, which has been a common and intractable issue that needs to be addressed urgently. Coating technology has been acknowledged to be the most economic and efficient approach to retard the metal corrosion. For several decades, polymers have been recognized as an effective anticorrosion coating material in both industries and scientific communities, as they demonstrate good barrier properties, ease of altering properties and massive production. Nanomaterials show distinctively different physical and chemical properties compared with their bulk counterparts, which have been considered as highly promising functional materials in various applications, impacting virtually all the fields of science and technologies. Recently, the introduction of nanomaterials with various properties into polymer matrix to form a polymer nanocomposite has been devoted to improve anticorrosive ability of polymer coatings. In this review article, we highlight the recent advances and synopsis of these high-performance polymer nanocomposites as anticorrosive coating materials. We expect that this work could be helpful for the researchers who are interested in the development of functional nanomaterials and advanced corrosion protection technology.

The reassigned pseudo Wigner–Ville transform in electrochemical noise analysis

Several different time–frequency transforms from signal processing were used to analyze electrochemical noise data to determine frequency components contained within the noise record and their time evolution.