Corrosion resistance of α- and (α + β)-Brasses in a descaling solution by a mixture of imidazole and hexadecyltrimethylammonium bromide

Abstract

Scaling is a major problem in many industrial processes. Oxide scales often formed on the surface of metals and alloys, and it is of high interest to descale it using effective and environment-friendly methods. Herein, the corrosion inhibition effect of the imidazole (IMI) mixed with the Hexadecyltrimethylammonium bromide (CTAB) for α- and (α + β)-brasses in a descaling solution (sulfamic (2%) and perchloric (4%) mixture) is studied at 295 K using electrochemical (potentiodynamic polarization measurements (PDP) and electrochemical impedance measurements (EIS)), inductively coupled plasma spectrometry (ICPS) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) techniques. Results show that the imidazole/CTAB mixture acts via adsorption at the alloy/solution interface. Potentiodynamic polarization results reveal that the imidazole/CTAB mixture behaves as a mixed type corrosion inhibitor. At the same time, those from EIS tests show that α-brass has a higher corrosion resistance compared to that of (α + β)-brass. Under optimum conditions, an inhibition efficiency of 95 % is achieved for both brasses. The morphological characterization by SEM/EDX and ICPS analysis confirms the efficacy of the mixture in protecting α- and (α + β)-brasses against corrosion by decreasing the dezincification factor. This study provides a new approach to control the brass loss and achieve desired surface quality using a less corrosive descaling solution and imidazole/CTAB as anti-corrosive additive.