Gold has, for some centuries, been among the most valuable natural resources on Earth. While at first the material was simply a means by which people could keep track of and easily move their wealth rather than simply transporting entire farms and grazing grounds, it eventually moved to being an important element in global finance. But it was only with the modern age of electronics that gold became useful not just as an economic tool but rather as a material that people could use. Gold sees a lot of usages of all kinds of electronics, from circuit boards to cellular phones, all of which are becoming more and more indispensable by the day.
But on its own, gold is merely pretty but not very useful to human beings. The most common way to transform gold from a costly sculpting material to a vital piece of electronics is through the process of gold plating. This process allows manufacturers to coat copper in gold so as to make it corrosion resistant, as gold is actually more than a little corrosion resistant while still maintaining impressive electrical conductivity properties. When plated with gold, vulnerable copper becomes a far less fragile material, making it useful in the printed circuit boards electrical conductors that people rely on every day.
When plating gold onto copper, the atoms of copper have a noted tendency to diffuses throughout the gold plated on it, tarnishing its surface and creating a sulphide or oxide layer, depending on the exact process used. Another material must be used as a barrier metal before copper can be plated with gold, however. Usually, this metal is nickel, which the copper is often covered by before the gold is added. The nickel provides a backing for the gold, making it more resistant to the inevitable wear that all electronics must endure over their lifespan, as well as reduce damage caused by the overall product from the microscopic pores in the layer of gold.
The gold plating process for electronics is oftentimes electrolytic gold plating. This is the process of using electrolysis to refine the metal into a high purity, yet at a very low cost. This process is usually done in bulk to large amounts of gold at once. When the gold is reduced to a semi-liquid state, it is coated with the electronic components already covered in nickel and mechanically plated on the device. Oftentimes, this method is selected because it is the cheaper, more effective method of making a particular electronic product.
The process is not without its hiccups, however. Some applications of using electrolytic techniques in gold plating are actually more expensive than using an electroless method. Additionally, some tools and methods will cause higher than desired losses in conductivity due to the fact that nickel has more electrical resistance than gold and copper. This reality requires that manufacturers often must be careful to be selective about what and where they plate their products with both gold and nickel, so as to prevent the worst of the unwanted side effects.