Material Sciencr question 5 State the three things required for galvanic corrosion to occur, and determine which of the following cases would provide protection against galvanic corrosion (circle the letter(s)). Low carbon steel with a scratched coating of tin. Low carbon steel with a scratched zinc coating. Medium carbon steel pipe connected to a brass fitting Solution a.) 1) Presence of two electrochemically different metals. 2) Metals surrounded by an electrolyte. 3) Metals are in electrical contact. b.) B. Low carbon steel with a scratched zinc coating..