Evaluation of plant extracts as corrosion inhibitors for Cu-alloys in river water

In power utilities, cooling water management is vital and one of the tasks is to combat scaling and corrosion in heat exchanger tubes. It is a general practice in power stations to add inhibitors to the cooling water to reduce the corrosion of the metals. Commercial inhibitors are very much effective but at the same time, disposal of such chemicals is considered to be hazardous to the environment. Hence, a need exists for environmental friendly corrosion inhibitors. From the little information available in literature, extracts of some plant materials have been found to inhibit corrosion of steels and copper alloys inriver water as well as in sea water. This paper describes theevaluation of environmental friendly plant extracts of Neem leaves, Turmeric, Coffee and Tea as corrosion inhibitors for copper alloys in river water. Copper alloys chosen were admiralty brass, Cu-Ni (70/30) and Cu-Ni (90/10). These extracts are evaluated by electrochemical polarization and impedance techniques.