Gold electroplating involves depositing a thin layer of gold on the surface of another metal and then using an electrochemical process to make it permanent and bonded to the surface. It is used for decorative purposes and for electronics.
The early history of electroplating can be traced back to around 1800 when an Italian chemist utilized gold in an electroplating process, and by 1805 he was able to plate several large silver metals. The process was perfected in the 1840s in Great Britain and Russia and later spread throughout Europe and the United States.
Electroplating uses electrical current to coat a conductive metal object with a thin layer of the metal. It changes the chemical and physical properties of the items that is being plated. It works by putting a negative charge on an object and then placing it in contact with a solution containing a metal salt. When the positive charged metal ions in the salt solution are attracted to the object, a metal bond is formed.
A leading use of electroplating is in the manufacture of jewelry. Generally copper and silver are used as a base, and over time the atoms from these metals diffuse into the gold layer. This causes a fading of the gold color on the surface. Electroplated gold jewelry has the advantage of being substantially cheaper than actual gold jewelry and it is perhaps most effective when silver is used as a base.
Gold plating is used in electronics to provide a layer that is both conductive of electricity and corrosion resistant. It is often used on copper, which is a highly corrosive metal, and is used on electrical connectors and on circuit boards. As with jewelry, the use of gold in electronics is in large part motivated by the expense of gold and gold used in the electroplating process on electronics can often be recovered and recycled.
While electroplating is highly effective at creating a bond, over time the underlying metal may come through. An additional problem is that achieving a uniform thickness with electroplating can sometimes be a challenge, especially on ridges and corners. Modern technology has specifically adapted the centuries old electroplating process to these problems.