Effect of (R⁺, X^–) salts addition on nickel corrosion in 1M sulfuric acid medium

Abstract

on the corrosion behaviour of nickel when submitted to 1M sulphuric acid medium. After one hour of immersion time, we noted an acceleration of nickel corrosion process after the addition of K þ ,Cl À and K þ ,Br À in the 1M H 2 SO 4 electrolyte. K þ ,I À exhibited an inhibition of the anodic Ni corrosion process whereas the phosphonium iodine (R þ ,I À ) acts simultaneously on both processes: it is a mixed inhibitor. Such result is due to the adsorption of the alkyl group C 8 H 17 which limited oxygen diffusion.EIS characterization of Ni exhibited surfaces after iodine salts addition allowed us simulating the resulting interfaces by electrical equivalent circuits. We concluded that (K þ ,I À ) addition decreased the material corrosion rate without changing the alteration mechanism. That result is due to the formation of NiI at the electrode surface. On the other hand, phosphonium iodine addition modifies the interface behaviour. In fact, the alkyl part of the organic iodine adsorbs at the surface preserving it against the corrosive action of the sulfuric acid.

An electrochemical impedance spectroscopy and potentiodynamic polarization study of the effect of unidirectional roughness on the corrosion of nickel

“…All the Nyquist plots were analysed by fi tting the experimental data to an equivalent circuit model. The model chosen for the fi tting was a commonly used model for Nickel [4] (Fig. 1).…”

“…Gilli et al [2], consider that the formation of a passive fi lm on nickel surface to be the main reason for the good corrosion resistance of nickel. There are different methods to protect nickel against corrosion in acidic media such as using inhibitors and surface modifi cation [4]. Typically, the general and localized corrosion behaviour of alloys depends on their roughness and passivation behaviour.…”

Ionic salt (4-ethoxybenzyl)-triphenylphosphonium bromide as a green corrosion inhibitor on mild steel in acidic medium: experimental and theoretical evaluation

“…34 The results achieved showed that phosphonium iodide addition modies the interface behaviour due to the interaction between the molecule and the material surface. Tetrahydroxymethyl phosphonium sulfate is a wellknown phosphonium salt that shows biocidal properties against sulfate-reducing bacteria (SRB), which produce sulfuric acid in oil industry.…”

Inhibition of carbon steel corrosion by 4‐vinylbenzyl triphenyl phosphonium chloride in HCl solution

“…The corrosion inhibition of triphenyl phosphonium salts on various metals (Ni, Zn and Fe) and alloys in acidic media was studied by Niass et al (2001), Said et al (2005Said et al ( , 2007, Troquet and Pagetti (2004), Bhrara and Singh (2007) and Khamis et al (2000). In all these studies, the phosphorus atom and the phenyl rings in the compounds were shown to be able to adsorb very well on the metal surface and form a protective layer, which in turn increases the effectiveness of corrosion inhibition with the increase in the concentration of the inhibitor, reaching in some cases 98 and 99 per cent inhibition (Nahlé and Walsh, 1995;Bhrara and Singh, 2007), respectively.…”