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 in river water as well as in sea water. This paper describes the evaluation 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.