The corrosion inhibition of carbon steel in 1 M HCl solution by Oestrus ovis larvae extract as a new bio–inhibitor

A new study on the corrosion inhibition mechanism of green walnut husk extract as an agricultural waste for steel protection in HCl solution

“…The optimum concentration of GWH extract was 400 ppm, while a higher or lower concentration could cause a reduction in the retardation coefficient. The same behavior was also found in other studies [ 17 , 25 ]. The range of E corr values for specimens with the green inhibitor was −532 to −507 mV.…”

“…This indicated that the steel substrate without the inhibitor had a higher thermodynamic propensities undergoing a corrosion reaction compared to the other specimens with the inhibitor. This observation has been noted in other studies as well [ 24 , 25 ]. Since the value of OCP during the exposure remained constant, it could present that no protective or passive layer was formed on the steel substrate [ 24 ].…”

“…C is the GWH extract concentration, θ is inhibition efficacy (% R × 0.01), and K ads is a constant related to the adsorption equilibrium. Inhibition efficacy formulas were found in other research [ [24] , [25] , [26] , [27] ].…”

“…To quantify the surface's inhomogeneity, a parameter called "n" was introduced. When the roughness of the steel was high, the value of n was close to zero, and whenever the surface roughness was low, n became 1 [ 25 ]. The same electrical circuit was also found in other studies [ 27 , 31 ].…”

Effects of Film Thickness of ALD-Deposited Al2O3, ZrO2 and HfO2 Nano-Layers on the Corrosion Resistance of Ti(N,O)-Coated Stainless Steel

“…The calculated values of the cathode and anode slope were all high. However, for the bare SS support, the cathodic slope was significantly higher than the anodic one, indicating a cathodic reduction detrimental to the anodic oxidation [58][59][60]. In the case of SS/Ti(N,O) coatings, the slopes were quite similar, such that it may be concluded that the hydrogen evolution and metal dissolution were almost in equilibrium [61].…”