Final answer:
Galvanic protection can be achieved through protective coatings, such as a zinc layer on steel, and the use of sacrificial electrodes, where a more reactive metal corrodes to protect the target metal.
Step-by-step explanation:
The two techniques used for galvanic protection are protective coatings and sacrificial electrodes. Protective coatings involve applying a layer of a more difficult-to-oxidize metal onto the surface of the metal to protect. For example, galvanized steel is protected by a thin layer of zinc that acts as a barrier to oxygen and moisture, preventing rust. This protection functions as both prophylactic, shielding the steel from oxygen, and cathodic after exposure, as zinc will oxidize before the steel.
The second technique involves the use of sacrificial electrodes, where a more reactive metal is attached to the object needing protection. The more reactive metal, often referred to as a sacrificial anode, will corrode in place of the protected metal. This process, known as cathodic protection, is highly effective in protecting structures such as pipelines and ship hulls.