Galvanic corrosion occurs when two metals of different nobility are in contact with each other and form a conductive path for electrons and ions to move from one metal to the other. The metal with the lesser nobility will be the one that ends up corroding and it’s also called the anode. Corrosion occurs most often when there is moisture present amongst the metals, with salt water being an even bigger cause. There are a few ways to help prevent the corrosion from happening, some of them include painting the metals, using plastic washers to separate the metals or using the same metals for construction.
This is a great example of why it is generally not desired using different metals or plating materials with mating contacts. A good chemical/cleaner with lubricant, shield, seal, surface protectant, or corrosion inhibitor properties may aid in helping prevent this corrosion.
Another great example of (galvanic) corrosion is the anode positive terminal of a car battery, as this is always the suspect (sus) terminal that has corrosion connection problems, which although this can also be blamed on outgassing emitted from the anode lead, of which a higher quality battery such as AGM types (absorbed glass-mat) rarely if ever have corrosion problems.