Inhibition of Pitting of Type 304L Stainless Steel by N‐Lauroylsarcosine

Abstract

The resistance of Type 304L SS to localized corrosion by aqueous chloride solutions is increased by addition of N‐lauroylsarcosine (NLS). The effects of N‐lauroylsarcosine concentration, chloride concentration, pH, and metal surface prepassivation on the efficiency of pitting inhibition were investigated. Linear current scan and potentiodynamic polarization methods were used to determine the pitting potentials. The electrode capacitance depends on NLS concentration,pH, and buffer content of the solution. Distinct changes in the NLS concentration dependence of the breakdown potential and capacitance occur near the critical micelle concentration of NLS. The results suggest that NLS is strongly adsorbed onto the electrode surface with the possibility that it forms a hemimicellar structure above a certain critical concentration. An inhibition effect in 0.1M normalNaCl is obtained with NLS concentration as low as 5×10−6M . The inhibitor efficiency depends on pH and increases with more efficient solution mass transfer. Possible mechanisms for the inhibition effects are discussed.

In Situ Scanning Tunneling Microscopic Study of the Corrosion of Type 304L Stainless Steel in Aqueous Chloride Media

“…2E, 1B, and 2B, apparently increases with decreasing pH. This is consistent with the pH dependence of its break-down potential reported by DeBerry et al (16). The surface of a SS sample immersed in 0.2M NaC1 solution at low pH (ca.…”

Inhibition of localized corrosion in chromium containing stainless alloys

“…Small additions of surface active species increases E P of 304 SS in chloride solutions (DeBerry & Vielbeck, 1986, 1988Vielbeck & DeBerry, 1984). Inhibitors based on the N -acylamino acid, such as N -lauroylsarcosine (NLS) are strongly adsorbed on the passive fi lm surface over a wide potential range.…”

“…Inhibitors based on the N -acylamino acid, such as N -lauroylsarcosine (NLS) are strongly adsorbed on the passive fi lm surface over a wide potential range. NLS may act as a surface buffering agent avoiding or delaying the critical conditions for pit initiation (DeBerry & Vielbeck, 1986). A hemimicellar layer may form on the passive fi lm surface acting as a barrier towards the ingress of aggressive anions (DeBerry & Vielbeck, 1988).…”

Biofriendly nanocomposite containers with inhibition properties for the protection of metallic surfaces

“…Some pathways have been suggested in order to replace hazardous chemicals [1,2,4]. One of the possible promising substituents is the N-lauroylsarcosine (NLS), which is the known corrosion inhibitor for the protection of iron, stainless steel, and other metallic compounds [5][6][7].…”