Evaluation of octadecylamine for the corrosion inhibition of Incoloy 800

Abstract

Indian pressurised heavy water reactors use Incoloy 800 for steam generators. The pH is maintained alkaline to check corrosion in secondary circuit by the addition of Ethanolamine (ETA). Effect of octadecylamine (ODA) for further reduction of corrosion is investigated. Incoloy was exposed to both steam and liquid phases at 200°C in an autoclave for 7 days. Concentration of ETA was kept constant at 6 ppm and that of ODA was varied from 6 ppm to 20 ppm. The film grown in liquid phase was thinner and enriched with Cr, while the film grown in steam phase had larger particles and mixed-ferrite in nature. Electrochemical Impedance spectroscopy studies suggested the presence of a barrier film under both liquid and steam phase oxidation. The addition of ODA was comparatively more beneficial in liquid phase. The study showed that ODA is a promising amine to inhibit the corrosion of Incoloy 800 in secondary water chemistry conditions.

Microscopic Structure and Binding Mechanism of the Corrosion-Protective Film of Oleylpropanediamine on Copper in Hot Water

“…The N–D stretching band could not be detected either (Figure S4b). This phenomenon has been reported recently by Kuilya et al that the N–H stretching of ODA is not observed in the case of the film formed with ODA on an Incoloy 800 plate . A similar observation has also been reported recently by Ida et al for the film formed with a film forming amine product (commercially available products containing a film forming amine as the film forming substance) on a carbon steel plate .…”

“…This phenomenon has been reported recently by Kuilya et al that the N−H stretching of ODA is not observed in the case of the film formed with ODA on an Incoloy 800 plate. 4 A similar observation has also been reported recently by Ida et al for the film formed with a film forming amine product (commercially available products containing a film forming amine as the film forming substance) on a carbon steel plate. 26 The disappearance of the N−H vibrational peak, as also cited and mentioned by Kailya et al, was a common phenomenon observed in the case of ODA and OLA adsorbed on Fe 3 O 4 nanoparticles by Pan et al 27 Importantly, the disappearance of the N−H band is another indicator of complexation, and Pan et al attributed their undetectability of the N−H band to complexation as well.…”

“…In this study, we have analyzed the film structure formed on the Cu metal surface in hot water by one of the representative FFAs, oleylpropanedimine (OLDA). Various applications of FFAs and their effectiveness have attracted much attention in the last decade in thermal power plants and various industrial steam generators. − The circumstances surrounding thermal power generation are shifting to ones that require more frequent shutdowns and layups as a result of the combined use of variable renewable energy. During the shutdowns, corrosion is more susceptible to occur due to oxidation caused by the O 2 uptake and lowering of pH caused by the CO 2 uptake.…”