" Passivation of Zinc Anodes in Marine Conditions"

A. Koopaee, Aghajani, M. Atapour,  R. Alibek

Materials Performance, September 2016, VOL. 56, NO. 6, page 2-4.

Abbstract :

Weather buoys are used for measuring meteorological data at sea and sending that data to coastal stations via a wireless network. Located under the buoy is a heavy ferrous metal counterweight box for balance and stability. This buoy counterweight is protected against corrosion by zinc sacrificial anodes. After about six months of operation, some of the anodes are sacrificed, while others are not, apparently because they experienced passivation. Test results show that the nonsacrificed anodes contain iron impurities and intermetallic phases in their microstructures. Thus, a simple anode acceptance test is the observation of impurities and intermetallic phases in the zinc anodes.