Pitting corrosion inhibition of 304 stainless steel in NaCl solution by three newly synthesized carboxylic Schiff bases

Abstract

Three newly synthesized Schiff base derivatives, sodium (E)-4-(nitrobenzylideneamino)benzoate (SNBB), sodium (E)-4-(benzylideneamino)-benzoate (SBB), and sodium (E)-4-(hydroxybenzylideneamino)-benzoate (SHBB) were investigated as pitting corrosion inhibitors for 304 stainless steel in neutral 0.1 M NaCl. Potentiodynamic polarization evidenced major shifts in pitting potential to more positive values with increasing inhibitor concentration. The scanning vibrating electrode technique (SVET) imaged metastable pitting in 0.1 M NaCl, but not in the presence of the inhibitor, indicating that it prevented pit nucleation. The inhibition performance was established under anodic polarization conditions, because only minute local anodic activity due to metastable pit formation could be observed when the steel was exposed to SNBB-containing solution, whereas the metal would undergo pit propagation at the same potential in the inhibitor-free solution. X-ray photoelectron spectroscopy (XPS) analysis evidenced chromium enrichment at weak points (pores) of the passive film at anodic polarization condition where sudden release of Fe cations is possible. In this way, the SNBB molecules will migrate to these sites to react with the Fe ions and form a chelate compound which will deposit finally at those sites and plug them, whereas no effect occurred at the open circuit potential (OCP).

Interplay between the composition of the passive film and the corrosion resistance of citric acid‐passivated AISI 316L stainless steel

“…Cr 3+ species are also reported to be the major chromium species in the passive films formed on stainless steels, either passivated or not 20–22 . As the main passivating agent, the amount of Cr 2 O 3 in the passive film is critical to its stability against localized corrosion 23,24 . The relative concentrations of each component in the Cr 2p 3/2 spectra of all samples are displayed in Table 1.…”

“…[20][21][22] As the main passivating agent, the amount of Cr 2 O 3 in the passive film is critical to its stability against localized corrosion. 23,24 The relative concentrations of each component in the Cr 2p 3/2 spectra of all samples are displayed in Table 1. The main finding is that chromium hydroxide predominates cies in the passive films can be described as follows 25,27 :…”

Comprehensive review of various corrosion behaviours on 316 stainless steel

“…The literature survey related to pitting corrosion is illustrated in Table 8. To investigate the pitting corrosion inhibitors, the sodium (E)-4-(nitro benzylidene amino)-benzoate (SNBB), sodium (E)-4-(benzylidene amino)-benzoate (SBB), and sodium (E)-4-(hydroxy benzylidene amino)-benzoate (SHBB) is the new synthesis bases for SS 304 in neutral 0.1 M NaCl solution [45]. In this process, the stainless steel 304 increases its pitting corrosion resistance at the localized layer in the passive layer.…”

Determination of Iron Valence States Around Pits and the Influence of Fe3+ on the Pitting Corrosion of 304 Stainless Steel

“…Pitting corrosion is a common localized corrosion form of stainless steel (SS) in chloride-containing environments [1][2][3][4]. Pitting is generally focused on a small area of a metal surface and causes devices to fail by perforation or initiates stress corrosion cracks [5,6].…”