The use of beta-carotene as environmentally safe inhibitor for Cu-Al-Ni alloyscorrosion in sulfide polluted chloride solutions

The stability of Cu-Al-Ni alloys used in the manufacture of NaCl in Egypt was investigated in sulfide polluted chloride solutions. Three different alloys, namely, Cu-10Al-5Ni, Cu-10Al-10Ni and Cu-10Al-45Niwereinvestigatedinchloride containingsulfide-ions using different electrochemical techniques including polarization and electrochemical impedance spectroscopy. The presence of sulfide ions in the chloride solution accelerates thecorrosion of Cu-Al-Ni alloys,whereas the increase of the nickel content in the alloy improves its corrosion resistance.?-carotene as eco-friendly corrosion inhibitor was used to protect the Cu-10Al-Ni alloys from corrosion in presence of sulfide ions. The corrosion inhibition efficiency reached >95% at 50 ppm of ?-carotene. The alloy surface was investigated by the scanning electron microscope and the surface constituents were analyzed by EDAX. Keywords: Corrosion; chloride, Cu-Ni alloys; EIS; sulfide pollution

Stability of Some Copper Ternary Alloys in Chloride Solutions Polluted by Sulfide Ions

The electrochemical performance of three copper alloys was investigated in simulated marine solution polluted by sulfide ions. Polarization techniques and electrochemical impedance spectroscopy, EIS, were used. Surface examination and morphological studies were employed. The results showed that the Cu-10Ni-10Zn alloy is more stable than the other two alloys. The alloy surface was covered by a barrier layer protecting it from corrosion. The thickness and resistance of the barrier layer formed on the Cu-10Ni-10Zn alloy increases with the increase of the immersion time. The mechanism of the corrosion process and the barrier film formation was discussed.  A comparison was made between the electrochemical stability of the three alloys in sulfide polluted chloride solution. The incorporation of Ni in the Cu2O barrier film leads to its stabilization and the stability is enhanced by the presence of Zn. The results leads to the recommendation of the Cu-10Ni-10Zn alloy for applications in sulfide polluted marine environments. Keywords:  Copper alloys, EIS, Polarization, SEM, Passive Films