Question 3-3A5

Galvanic corrosion occurs when two dissimilar metals are in electrical contact and exposed to an electrolyte, such as moisture, rain, or saltwater. This creates an electrochemical cell, similar to a battery, where the more "active" metal (anode) corrodes at an accelerated rate, sacrificing itself to protect the less active metal (cathode). This is a critical consideration in amateur radio for antenna systems, ground connections, and outdoor equipment where different metals (e.g., copper wire on an aluminum mast, brass connectors) are often used together in damp environments. A) Electrolysis is a process driven by an *external* electric current to induce a non-spontaneous chemical reaction, not the spontaneous corrosion between dissimilar metals. B) Stray current corrosion results from unintended electric currents leaking from *external* sources, not necessarily from the interaction of dissimilar metals. C) Oxygen starvation corrosion (or differential aeration corrosion) involves a *single* metal exposed to varying oxygen levels, not the interaction of dissimilar metals.