Passivation of Zinc Anodes in lakewater
Passivation of Zinc Anodes in lakewater
(OP)
Zinc hull type anodes galvanically protecting low carbon steel (A588, CorTen Steel). 15 yrs in service and no noticable section loss of anodes. Anodes have developed a tough, chalky scale. This scale acts as a resistor in the galvanic circuit.
Water Analysis: pH=7, conductance=135umhos, SO4=28ppm, Cl=12.9ppm, Total Dissolved Solids = 104mg/l.
Could this scale be zinc oxide? Would mag anodes be better suited for this application?
Water Analysis: pH=7, conductance=135umhos, SO4=28ppm, Cl=12.9ppm, Total Dissolved Solids = 104mg/l.
Could this scale be zinc oxide? Would mag anodes be better suited for this application?





RE: Passivation of Zinc Anodes in lakewater
To be absolutely sure if any other anode will work you will probably need a quick survey around what you are protecting. The anodes around the water where I worked were of a mixed variety and all seemed to work.
Offsite I have seen offsite a tremendous variability in marine anodes. If there is any doubt, as I mentioned, get a survey of the potential around equipment.
If they are protecting the equipment stay with zinc and kept them maintained.
RE: Passivation of Zinc Anodes in lakewater
Periodic cleaning of the anodes is not practical though. This would require heavy lifting equipment and significant manpower. I think a better alternative would be to go with a different anode material - something that would not react with the dissolved oxygen in our lakewater.
RE: Passivation of Zinc Anodes in lakewater
Cathodic protection may be a better option.
I would contact a specialist in this area.