Acid‐dyes as corrosion inhibitors for mechanically pretreated aluminum

Abstract

Purpose -The purpose of this paper is to provide acid-dyes, known for the dyeing of porous aluminum oxide films, as inhibitors of the corrosion of aluminum in neutral chloride solutions. Design/methodology/approach -Potentiodynamic polarization plots are recorded on mechanically pretreated aluminum using a three-electrode cell containing 0.01 M NaCl solution with or without 0.025 mM of the acid-dyes monosulfonic methyl orange (MO), disulfonic chromotrop RR (CH), disulfonic alphazurine A (AZ) and trisulfonic light green SF yellowish (LG). The X-ray fluorescence technique is used in certain cases for the estimation of sulfur net content of the surface of the probes and thus of the concentration of the adsorbed dye. Findings -The inhibition efficiency of acid dyes on corrosion of mechanically pretreated aluminum seems to be related more to the presence of a following quinonoid structure which probably contributes more to the formation of mono-or bi-dentate compounds with the aluminum cations in the substrate than to the number of sulfonic groups in their molecule. Thus, the triphenylmethane dyes LG and, to a greater extent AZ, having this quinonoid structure means they are more efficient as corrosion inhibitors in near-neutral chloride solution than the azo dyes MO and CH, that do not have it. Practical implications -Selected acid-dyes such as triphenylmethane sulfonic-dyes, which have found wide application in the dyeing industry, seem to protect aluminum against the corrosive action of chlorides. Originality/value -This paper is intended to be the nucleus for the electrochemical studies of the effectiveness of acid dyes as corrosion inhibitors for aluminum.

Inhibition Effect of Triphenylmethane Dyes for the Corrosion of Carbon Steel in CO2-Saturated NaCl Corrosion Medium

“…Li et al studied the inhibition effect of crystal violet (CV) on the corrosion of cold-rolled steels in 1.0 M HCl solution and found that it is an excellent inhibitor [ 14 ]. Careful examination of the data reveals that triphenylmethane dyes can block the active sites of corrosion and reduce the corrosion current density, thereby inhibiting the corrosion of metal in hydrochloric acid [ 15 , 16 , 17 ]. Despite numerous studies on dyes as corrosion inhibitors, the performance of triphenylmethane dyes in CO 2 corrosion remains unexplored, which represents a novel direction for corrosion research.…”

Effect of Various Forms of Aluminum 6082 on the Mechanical Properties, Microstructure and Surface Modification of the Profile after Extrusion Process

“…In study [31], xylenol orange was tested as a corrosion inhibitor for aluminum in trichloroacetic acid. In study [32], with a variety of dyes, methyl orange was used as a corrosion inhibitor for mechanically pretreated aluminum. Yet another study [33] used methyl orange as a dye adsorbed onto films of anodized aluminum oxide for pH sensing purposes.…”

“…Although methods for modifying the aluminum surface by anodizing and further processing are known [23,24,27,28,32,33,36,37], such tests have not been performed on recycled alloy 6082. This article shows practical examples of surface treatment of 6082 alloy: solid and its scrap.…”