Galvanic Effect and Alternating Current Corrosion of Steel in Acidic Red Soil

Abstract

Alternating current (AC) corrosion behavior of carbon steel–copper couple in acidic red soil was studied by means of the electrochemical test, mass loss, X-ray diffraction (XRD) and scanning electron microscope (SEM) characterization. Mathematical models were established to expound the impacts of AC and galvanic effect on the corrosion mechanism. The results demonstrate that the corrosion rate of the galvanic couple is positively related to AC intensity. Galvanic effect and AC synergistically aggravate the corrosion of steel. The composition of α-FeOOH declines while γ-FeOOH is increased with AC interference. Based on the statistical model, the galvanic effect has a more significant influence on steel corrosion compared with AC.

Effect of HSO3− and alternating current on corrosion behaviour and mechanism of CoCrFeNi HEA in a simulated marine environment

“…12), and the continuous production of oxygen accelerates the oxidation process of SO 3 2- and the cyclic acidification, thus generating a large amount of H + . Additionally, under AC application, with the increase in the migration rate [60] and adsorption [25,61] of ions, the reaction between harmful ions and oxides/hydroxides in the passivating film is intensified, which makes the corrosion of the HEA more serious and even difficult to form a passive film. On the other hand, in the negative half cycle of AC, the hydrogen evolution reaction is accelerated (Reaction.…”

Effect of pH on corrosion behaviour of CoCrNi MEA imposed by alternating current in Na2CO3/NaHCO3 solution

“…The reactions are as follows: As the scanning potential continues to rise, the surface potential of the working electrode is higher, and the above reactions could be inhibited. Especially in the case of applied AC, the MEA surface mainly occurs with the hydrogen evolution reaction [47], and a large amount of H + ions are produced. Finally, the above valence change process tends to be stable again, and the Cr (III) species in the solution are deposited again, forming a thicker passivation film and improving the corrosion resistance of the MEA.…”

“…The function of AC is reflected in two aspects: (1) In the positive half cycle of AC, the water electrolysis is stimulated (reaction ( 12)), and more generated H + ions are involved in the corrosion process. Additionally, the migration rate [54] and adsorption [47] of ions are accelerated under AC inference. Thus, the corrosion reaction is intensified, which greatly induces the occurrence of metastable pitting.…”