Nephelium lappaceum Extract as an Organic Inhibitor to Control the Corrosion of Carbon Steel Weldment in the Acidic Environment

Abstract

Organic inhibitors have been considered as an effective way to control the corrosion of carbon steel weldment in an acidic environment. This work proposes a new green organic inhibitor made of extract of rambutan fruit (Nephelium lappaceum) peel and aims at analyzing its corrosion inhibitor properties and protection mechanism. Specimens of carbon steel weldment were tested for their corrosion by using electrochemical and immersion methods in 1 M HCl solution containing 0 to 6 g/L of Nephelium peel (NP) extract. Results showed that, in the same solution, the corrosion rate was measured to be higher on the weld metal zone than that of base metal zone, which could be related to the coarser grain of the weld metal zone and the stability of the formed oxide layer. The addition of NP extract was found to increase the stability of the oxide layer, thus increasing the corrosion resistance of the specimens. The maximum inhibition efficiency of the NP extract was reached at 97% for weld metal with 5 g/L of extract, at 80% for the heat affected zone with 5 g/L, and at 70% for base metal with 4 g/L. This work reveals the particularity of different weldment zones to the different needs of inhibitor concentration for obtaining the optimum corrosion protection.

Tithonia diversifolia Extract as An Eco-friendly, High-temperature Corrosion Inhibitor for 304 Stainless Steel in Acidic Solution: Experimental and Quantum Chemical Studies

“…The maximum Ecorr of 304 SS shifted by 45.63 mV compared to the blank. Based on the literature, the inhibitor can be cathodic or anodic when the displacement in Ecorr is more than 85 mV, and if the displacement of Ecorr is less than 85 mV, the inhibitor acts as a well-known mixed type [2,15]. Because the displacement of Ecorr at TDLE is less than 85 mV, we suggest that it is a mixed type of corrosion inhibitor for 304 SS in 1 M HCl.…”

“…The inhibitor reduces the corrosion rate of 304 SS by chemisorption [27]. The Eyring transition state equation is an alternative formulation of the Arrhenius equation to determine the values of enthalpy (∆𝐻) and entropy (∆𝑆) [2,15]. The values of ∆𝐻 and ∆𝑆 can be calculated by Eq.…”

“…The current density is directly proportional to the corrosion rate, so this result is in good agreement with theory. In general, the corrosion rate increases with temperature, because of a decrease in over-potential hydrogen evolution [15].…”

“…Recently, an organic inhibitor from natural products has been widely developed and applied. Almond gum, a mixture of rosemary and cinnamon cassia oil, Pterocarpus santalinoides leaf extract, Thevetia peruviana flower extract, Nephelium lappaceum extract, Akebia trifoliate koiaz peel extracts, and maple leaf extract can improve steel corrosion resistance in acid solution [9,11,[15][16][17][18][19]. Unfortunately, these compounds do not inhibit 304 SS corrosion effectively at high temperatures.…”

Detection of Hydrogen Bubbles Produced by Corrosion Inhibition of Metal Weldment Using Machine Learning

“…The advantages of organic compounds are they are non-toxic, affordable, renewable, and easy to produce [5,6] but still need a lot of research to fully understand their performance and mechanism. On another side, non-organic inhibitors have already been studied and tested [7][8][9].…”