The effect of surface modification on the corrosion protection ability of the passive films of sensitized UNS S31803 duplex stainless steel

Abstract

The influence of sensitisation heat treatment, surface roughness and repetitive cyclic voltammetry (RCV) procedure (that was used to create passive films on the surface of sensitised samples) on the corrosion behaviour of UNS S31803 duplex stainless steel was evaluated using sodium hydroxide etching, double-loop electrochemical potentiodynamic reactivation (DLEPR), potentiodynamic polarisation, Mott-Schottky analysis, X-ray diffraction and optical microscopy techniques. The results showed that prolonged sensitisation time leads to the formation of defective passive films on the surface. In addition, as the substrate surface roughness decreases, the defect concentration in the resulting passive film decreases. Moreover, thick passive films that were created at a high number of RCV cycles contain fewer defects than the thin ones. Finally, the specimens with smooth surfaces, thick passive films and low degree of sensitisation exhibit high corrosion resistance due to their intact passive layers formed on their surfaces.

Characterization of Anodic Films Produced on Anodized AA1050 Aluminum Alloy: Effect of Bio-additive

“…Tafel polarization tests were performed in a conventional three-electrode cell containing 3.5 wt pct NaCl electrolyte at room temperature with an Ag/AgCl reference electrode (impedance of the reference electrode was lower than 3 kX), anodized sample as the working electrode (with exposed area of 0.785 cm 2 ) and the platinum plate counter electrode using Ivium A32700 potentiostat/galvanostat. In all polarization tests, the samples were polarized from À 300 to + 300 mV with respect to open circuit potential (V OCP ) with a potential scan rate of 1 mV/ s. [34,35] The corrosion rates were calculated according to ASTM G102 (Eq. [1]) [36] CR…”

Corrosion behavior and electrochemical corrosion of a high manganese steel in simulated marine splash zone

“…A three-electrode system was adopted with platinum as auxiliary electrode (CE), KCl-saturated calomel electrode as reference electrode (RE), the samples with rust layer of 1cm 2 area after dry wet alternate corrosion for 24, 72, 168, 288, 432 and 600 h were used as working electrodes, and the electrolyte is 3.5% sodium chloride corrosion solution. The corrosion behavior of the samples were detected by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve [20,21]. The process is as follows: the sample steel was put into electrolyte…”

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“…In order to further explore the inhibition effect of corrosion inhibitors, fast Fourier transform (FFT) was performed on the time-domain spectrum, and the transformation formula is shown by equation (1) [28,31]:…”