Influence of Casting Temperature on Electrochemical Behavior of Al-Zn-In Sacrificial Anodes

Aluminum anodes have been widely used in the cathodic protection of marinestructures. however there are conditions in which these anodes become passivated or face somelocalized or unwanted corrosion, which influences their efficiency. addition of alloying elementssuch as zn and in not only have improved the efficiency ofthe anodes but also the effect ofcastingparameters such as ultra melt temperature tm , mold temperature and grain refiners can adverselyinfluence the capacity of aluminum anodes. in this work the effects of ultra melt temperature andmold temperature have been studied on the potential and current capacity of al-zn-in anodes.electrochemical polarization and nace standard methods were used to evaluate the anodicbehavior, potential and current capacity of the anodes. it is shown that metallic molds havinghigher temperatures could provide better condition for obtaining homogenous structures with minorinclusions. the optimum condition of anode operation may be provided where mold and pouringtemperatures equal to 400°c and 710°c respectively, in which a fine structure, phase distributionand lack ofcasting faults are obtained. the microstructures that can provide a homogenous anodicdissolution bring by itselfoptimum efficiency ofthe anodes.