Salen type additives as corrosion mitigator for Ni–W alloys: Detailed electronic/atomic‐scale computational illustration

Abstract

It is imperative to study the long‐term corrosion problems of nickel alloys in acidic medium due to breakdown of their passive oxide film. Focus of this work is to enhance the knowledge of adsorption of organic additives ‐1‐((E)‐(2‐((E)‐(2‐hydroxynaphthalen‐1‐yl)methyleneamino)phenylimino)methyl)naphthalen‐2‐ol (OPD) and 1‐((E)‐(2‐((E)‐(2‐hydroxynaphthalen‐1‐yl)methyleneamino)phenylimino)methyl)naphthalen‐2‐ol (PPD) onto the surface of Ni–W alloy. Deducing the scenario of competitive adsorption of salen‐type symmetrical Schiff bases (OPD and PPD) as additive molecules on Ni–W alloy surface at molecular level was studied by density functional theory (DFT), Monte Carlo simulation (MC), molecular dynamics simulation (MD) and radial distribution function (RDF) analysis. Obtained intrinsic molecular parameters from DFT shows a strong conformity to the corrosion efficiencies of experimental results. From the simulation results, PPD showed the higher polarization (650.707 a.u.), higher binding energy (Ebinding = 1132.241 kJ/mol), larger negative interaction energy (Einteraction = −1132.241 kcal/mol), and negative value of adsorption energy (Eadsorption = −195.55 kcal/mol) and flat‐lying spatial orientation than that of OPD. These results suggested that the role of spacers play a vital role in the adsorption process, that is, larger spacer containing PPD has strong binding interaction and high surface area coverage with Ni–W alloy surface than shorter spacer OPD. Significant findings from DFT global descriptors, MC, MD and RDF analysis ratifies the corrosion efficiencies (PPD > OPD) of experimental outcomes, which correlates positively with the larger isomeric spacer. Overall, the present study, reports offers the corrosion resistance impact of OPD and PPD additives, revealing the fact of PPD as effective one and OPD as moderate ones for Ni–W alloys, thus validating the experimental results.

An Experimental and Theoretical Investigation of the Efficacy of Pantoprazole as a Corrosion Inhibitor for Mild Steel in an Acidic Medium

“…To create the charge density curve, referred to as the sigma profile, it is essential to perform calculations centered on the conductor-like screening model (COSMO) (Figure 3). COSMO operates on molecular-shaped cavities, which are characterized by partial atomic charges and serve as a representation of the electrostatic potential [15,[39][40][41][42]. As seen in Figure 3 (peaks in the σ-profile at the screen charge density values near −0.01 and 0.01 e/Å 2 ), the inhibitors operated as an acceptor/donor of H-bonds in the process.…”

Experimental and theoretical investigations of new Schiff base compound adsorption on aluminium in 1 M HCl

“…The density functional theory (DFT), MC, and molecular dynamics simulations for this work were performed using Material Studio. The COMPASS forcefield in Material Studio's Forcite module was used to change the geometries of the inhibitor, water, and hydronium ion (H3O + ) [32][33][34][35][36][37].…”

“…A conformer search (Boltzmann jump technique; the number of conformers: 8000; utilizing the COMPASS II forcefield) was undertaken in the early phase of the procedure in order to acquire the lowest feasible starting energy for the molecule while speeding up DFT computations [29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Calculations for DFT were started with the lowest-energy conformer shown by the image in Figure 5.…”

Ab Inito Exploration of Nanocars as Potential Corrosion Inhibitors

“…Moderately high value of chemical softness ( Table 1) and low value of hardness are also expected values that support these inhibitors as relatively high reactive entities with the adsorptive aptitude when they are in the vicinity of the metal surface. Polarizability is a quantum descriptor related to the distribution and distortion of electron density [69,70]. A larger value indicates easiness distribution of the electron density to a metal surface.…”