What leads to the formation of patina in copper

Almost every single metal on this earth is considered a strong and stable material. But even after that, the powerful environment also affects these metals. Prolonged exposure to air can lead to the oxidation process in iron. Similarly, copper is also susceptible to such alterations and, for this reason, develops a green patina. The reason for the same is that the oxygen in the air leads to the formation of the patina.

What is copper?

Copper is a reddish-brown chemical element closely related to gold and silver. Copper is a malleable metal and, therefore, is used to make coins, utensils, etc. It is also highly conductive in nature and conducts heat and energy equally well. It is also one of the oldest metals discovered and used by the human race.

What is the reason why copper turns green?

It is due to the oxidation process of copper that turns green. When left exposed to air and water, it leads to the formation of a thin green layer on the surface of the metal. This green substance is known as copper carbonate. But unlike the iron that weakens when it oxidizes, the green patina does not affect the quality of the metal. In fact, some people say that the green substance protects the surface of the metal. Oxidation is a slow process and takes time and before turning green, copper can turn dark brown and black. The green material is also called patina.

What’s the use of patina?

It may seem useless, but the patina also has some uses. During the last years, Greek artists used to use this green patina in their works of art. It was called ‘verdigris’ which means “green of Greece”. It was considered to be the brightest green pigment available, but due to its low durability, it was abandoned by artists at the end of the 19th century. Another use of this patina was dating objects. It was popular in the antique trade business, where it was thought to preserve the integrity of the object. The patina is also used in some functions of electrical engineering.

Common Patina Examples

One of the most famous examples of copper patina is the well-known Statue of Liberty. Not many people know that this world-famous landmark is made of copper. It is known for its light green color that is nothing more than patina. This happened when the copper material of which the statue is made reacted with water and air and oxidized for a period of years. Old pots and guns also develop patina on their surface as they age. For some people it adds to the character and value of the product. The best part is that it can be easily cleaned with a little effort.

How to get rid of patina?

Keeping copper utensils in direct sunlight will help prevent the formation of green patina. It is the oxygen that leads to the formation of the green layer and, therefore, preventing oxygen from coming into contact with the metal will stop the patina formation. An excellent way to get rid of patina is to use a solution of salt and vinegar. After cleaning the patina, the surface of the article must be cleaned from the surface to avoid watermarks.