Copper plating is a coating of copper metal on another material, often other metals. Plating is designed to increase durability, strength, or visual appeal, and copper plating specifically is often used to improve heat and electrical conductivity. Copper plating is seen most often in wiring and cookware.
Occasionally, copper plating is used for decorative purposes, giving objects a brassy look. Copper plating is more often used, however, for electrical wires since copper conducts heat extremely well. Additionally, many circuit boards are plated with copper.
Since copper is an exceptional heat conductor, copper plating is popular in cookware as well. The speed with which copper heats allows for even surface heat, and, therefore, allows for more even cooking. Professional chefs generally used solid copper cookware, usually lined with steel for increased durability, but these are expensive and not generally in the budget of a hobby cook. Plated pots and pans are usually aluminum or steel plated with copper. This plated cookware still allows for the benefits of copper heating without the expense of the pure copper alternatives.
Copper plating is often applied by a process called electroplating. Electroplating is simple enough to be done at home, but can be dangerous so is not recommending for the inexperienced. Simple setups of electroplating are often used in high school science demonstrations, but nickel rather than copper is most often used as the plating substance.
A simple setup for electroplating requires the object to be plated, a battery with positive and negative connecting cables, a rod of solid copper, and a copper metal salt, such as copper sulfate, that has been dissolved in water. The object to be plated and the copper rod are both placed into the salt solution and connected to the battery: the copper rod to the positive and non-copper object to the negative. In this setup, the non-copper object becomes the cathode, and the copper rod becomes the anode.
When the salt is dissolved in the solution, the molecules break apart into positively charged copper and negatively charged sulfur ions. Since the cathode is hooked to the negative output of the battery, it becomes negatively charged. The negative charge attracts the copper ions in the solution and they adhere to the outside of the object. Meanwhile, the copper atoms from the anode are being pulled into the solution, replenishing those that are attaching to the non-metal object.
This process is more complicated when attempting to plate iron or steel with copper. Copper will passively adhere to iron-based substances when placed in a solution of this type. Passive transfers do not retain the plating, so are useless for this purpose. In order to plate iron or steel with copper, a coating of nickel must be applied to the iron first.