Galvanic Effect
Galvanic effect is the phenomenon where objects that have dissimilar thermodynamic potentials form an electrical current when in contact with a conducting medium. In technical terms, its the physical and chemical effect that occurs when two different metals are immersed in a common electrolyte or when they are in close contact with each other in an electrolyte solution. A galvanic effect is also known as bimetallic effect or galvanic corrosion.
The galvanic effect occurs when two dissimilar metals are placed in contact with each other and then immersed in an electrolyte, usually a common salt or water solution. The thermodynamic potential difference between the two metals causes the electrons to flow from one metal to another. The metal that performs the oxidation—losing electrons—is referred to as the anode and the metal that performs the reduction—gaining the electrons from the anode—is referred to as the cathode.
One of the most known uses of the galvanic effect is in batteries, where two different metals are combined to produce electrical energy. When a battery is connected to a load, electrons move from the anode to the cathode, creating a current. Batteries are composed of an anode, a cathode and an electrolyte, which is the medium that carries the electrical current. The electrolyte is made of some type of salt solution, such as potassium hydroxide, sodium hydroxide, or even plain tap water. This solution is what allows the electrons to move from one metal to the other.
The galvanic effect can also be found in some industrial processes, such as plating and electroplating. Plating involves immersing a metal in an electrolyte solution and then passing an electrical current through the solution. This causes electrons to move from the metal that is being plated, which is the anode, to the metal that the plating is being applied to, which is the cathode. This process is known as electrolysis and has a number of industrial and commercial applications, such as in the manufacture of coins and other metal objects.
The galvanic effect can also be observed when there is corrosion, as in the case of metal structures exposed to the elements over long periods of time. When two dissimilar metals are exposed to water, or to air containing water, they create a galvanic cell that can cause corrosion of one or both of the metals. This corrosion can be accelerated or inhibited by the electrolyte that is present, depending on whether that electrolyte aggressively removes the metals or protects them from the environment.
The galvanic effect has important applications in biology and medicine, as well. For instance, most types of metal implants, such as hip replacements and dental prostheses, use the galvanic effect to help encourage bone growth. By connecting a titanium metal implant, which acts as the anode, to a stainless steel surface, which acts as the cathode, a weak electric current is formed between the two. This current encourages bone cells to grow around the implant, resulting in a strong and stable implant.
Overall, the galvanic effect is a widely observed phenomenon that has a variety of industrial, commercial, and medical applications. By understanding the principles of the effect, and how it can be used to our advantage, scientists and engineers can develop new and better techniques for improving our everyday lives.
