Understanding Copper Patina/Corrosion
Copper is an ancient metal responsible for the transition of humans from the stone age to the metal age. Being a versatile metal copper led to the flourishing of various ancient civilizations like Mesopotamians, Egyptians, Romans, Indian and Japanese. For the last 10,000 years, humans have used copper in jewelry, utensils, tools, weapons, architectural monuments, relics of which have been excavated and recovered buried in earth and oceans intact attesting to copper being sturdy and superior metal.
A very important concern that bothers a potential buyer of Copper Bathtub or copper kitchen sink is whether copper rust/corrode and its impact on longevity, performance, and retaining exotic beauty?
All metals undergo oxidation, a chemical inevitability. Copper’s exposure to air, water – especially salt water, heat, and acidic compounds can induce oxidation imparting verdigris (aqua-green) texture termed as Patina, which in fact acts as a protective film preventing further corrosion.
The first stage of Patina triggers when the copper reacts with oxygen in the air to form copper (I) oxide (Cu₂O) imparting a reddish tinge. With the passage of time, this ongoing chemical reaction with oxygen forms copper (II) oxide (CuO) imparting a black tinge. Another chemical reaction with sulfur in polluted air forms copper (II) sulfide (CuS). Copper (II) oxide (CuO) and copper (II) sulfide (CuS) over several years to decades react with carbon-di-oxide (CO2) in air and hydroxide ions (OH–) from water to form three compounds:
- Cu2CO3(OH)2 – Malachite
- Cu3(CO3)2(OH)2 – Azurite
- Cu4SO4(OH)6 – Brochantite
This physical effect on copper due to inevitable chemical reactions is termed PATINA, truly a “Living and Evolving Finish”. Patina is absolute proof that the copper kitchen sink or copper bathtub is made of genuine and authentic pure copper.
Is Patina Reversible?
Copper patina is a desirable texture aging and many people like the look of tarnished copper sinks, copper tubs, and copper pots, but others prefer the look of reddish-brown copper. The good news is that Patina is reversible.
Coppersmith Creations has a state-of-art manufacturing facility with highly skilled artisans producing high-quality 16-gauge lead-free durable hand-made copper kitchen sinks and copper bathtubs in polish copper, nickel, tin, antique finish, and a variety of exotic paint finishing/lacquer coating imparting resistance to rust and corrosion for decades. Our entire range of copper kitchen sinks and copper bathtubs will look young forever and just need minimal routine cleaning with a soft cloth, mild detergent/soap to take care of any chemical reaction thereby preserving the stunning and luxurious appearance for decades.