The Suppression of transformation of γ-FeOOH to α-FeOOH accelerating the steel corrosion in simulated industrial atmospheric environment with a DC electric field interference

Abstract

The initial corrosion of steels exposed to the simulated industrial atmospheric environment with a direct current (DC) electric field for 30 days was investigated using weight loss, electrochemical and characterisation methods. The results show that the steel weight loss increased with the increase in DC electric field intensity. The steels exposed to the DC electric field interference exhibited a higher corrosion rate than the blank samples during the exposure. The microstructural studies reveal that the existence of the DC electric field favours the growth of the γ-FeOOH, while suppresses the transformation of γ-FeOOH into α-FeOOH during the 30 days' exposure, as a result of decreasing the protective ability and stable property of the rust layer. The amount of porous γ-FeOOH enhances the transmission of oxygen and conductivity of the whole rust layer. All these induce an accelerated effect of DC electric field on the initial steel corrosion in simulated industrial environment.

The effect of magnetic field pretreatment on the corrosion behavior of carbon steel in static seawater

“…5(c) ). According to Gu et al , 40 petal-like and the worm-like structures may be an intermediate product of incomplete oxidation in the corrosion process. Furthermore, the compactness of corrosion products on the surface of the carbon steel was significantly enhanced by increasing the pretreated magnetic field strength.…”

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

“…The formation and transformation of Fe oxide are important corrosion processes for steels. Some previous studies [51,52] have concluded that γ-FeOOH transforms to α-FeOOH by dissolution of γ-FeOOH and precipitation of α-FeOOH with the coexistence of SO4 2− and Fe 2+ . In the positive branch of the AC signal, Fe 2+ and H + shift out of the electrode/electrolyte interface while SO4 2− pulls to the electrode/electrolyte interface.…”

Electrochemical behavior of X70 and X80 pipeline steels in a simulated soil environment with and without the presence of chlorides

“…The addition of Clion to slightly alkaline carbonate-bicarbonate resulted in cloud-like porous corrosion products in both the X70 and X80 steels, indicating the presence of akageneite (β-FeOOH) [56]. β -FeOOH has a loose structure which allows further corrosive attack and increases the pitting tendency [64]. In a highly alkaline carbonate-bicarbonate solution, the top surface of the X70 steel (Figure 12(c)) shows compact rust layer consisting of flowerpetal formations of goethite phase with disks of magnetite and small dispersed crystals of siderite phase, whereas the X80 steel shows a surface largely covered by flat disks of magnetite with siderite crystals and cotton-ball structures of goethite [61] (Figure 13(c)).…”