Following short-term and long term electrochemical evaluations of twenty-three cast alloys varied around the baseline alloy composition of 3.5 weight percent (w/o) zinc, 1200 parts per million by weight (ppmw) silicon and 150 ppmw indium, scanning electron microscopic evaluations were made including elemental evaluations of interesting features. The presence, location and electrochemical behavior of Fe/Si rod impurities within the bulk alloy was documented. Some surface segregation of excessive element additions appearing to have resulted in passivation was also documented.