SELF ASSEMBLED FILM OF THIOL COMPOUNDS ON BRONZE

摘要

2-aminoethanethiol (AET) and 2-mercapto-ethanol (ME) compounds have been studied for protection of bronze (CuSn5Pb5Zn5) against corrosion in test solution simulating urban rainwater (pH 5, including 0.2 g/L of each Na_2SO_4 and NaHCO_3). The protection efficiencies were evaluated with electrochemical impedance spectroscopy (EIS) and potentiodynamic (PD) measurements. The surface of corroded samples was characterized by X-ray elemental energy dispersion spectroscopy (EDS) and scanning electron microscopy (SEM). The studied molecules are both capable for strong interaction with the copper content of bronze alloy. Also, it was anticipated that intermolecular interaction could arise due to presence of additional -OH and -NH2 end groups. For this purpose, the corrosion protection efficiency of these compounds has been investigated separately, as well as a mixture with 1:1 of molar ratio between two compounds. These bi-functional molecules exhibit strong adsorptive interaction with the alloy's surface, via -SH groups. Then the production of cupric/cuprous oxide has been diminished oin the surface, the surface was protected with strongly adsorbed organic layer. It was also shown that the mixture could provide better protection efficiency, because of strong intermolecular attractions between AET and ME.