Cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. This can either be done by using a sacrificial anode made from sink or similar material, or by applying an external direct current.

So… what has that to do with shaving? Well… normally it don’t, but J Duggan’s 1971 patent application on behalf of Warner Lambert Co combines the two.