Gold Plating
Gold plating is an extremely typical process in commercial industries such as jewelry, in the plating of silver or copper which is likely its most common application, but it can also be used in other industries as well. Although it is an expensive process and other, more-cost efficient metal choices can be used, other applications and industries besides jewelry that gold plating is utilized in include: electronics, in order to plate copper electrical parts such as electronic connectors and printed circuit boards (PCBs); office, for plating of name plates such as office, desk and door nameplates; residential, for use in decorative applications such as vases, plaques and a variety of wall art (in which it is often referred to as gilding); industrial, in which it can be used in engineering applications; and aerospace, for use in the plating of both commercial and military aircraft components.
In addition to the four main categories of chemistries used in gold plating, there are two main types of gold plating: soft gold plating and hard gold plating. Soft gold plating is accomplished with pure gold, which is a naturally soft and malleable precious metallic element. Hard gold plating, on the other hand, is achieved with gold with has been alloyed with another metallic element such as nickel and/or cobalt in order to make it more dense and durable. Gold can be plated by either an electrolytic plating process (electrochemical) or an electroless plating (chemical) process. For the electroplating process, the part to be plated is immersed into a solution, which is most often water. Operating as a cathode, this metal part is connected to the negative charge of battery. Next, the gold is placed into the solution, acting as an anode, and is connected to the positive charge of the battery. For deposition of the gold, ionization occurs and dissolves the gold, drawing the positively-charged ions to the metal part's negatively-charged ions. Electroless gold plating is also an immersion process; however, instead of water the bath is typically formed from chemical solutions such as potassium hydroxide, potassium cyanide and potassium borohydride. In addition, no external electrical equipment is required since electroless plating is solely dependent upon a chemical reaction.
