Plating

Plating is a surface covering in which a metal is put on another metal surface. Plating has been done for hundreds of years, and it is important for modern technology. 
Plating is used to decorate objects, prevent corrosion, to harden, to improve wearability, to reduce friction, to allow painting, to alter conductivity, and for other purposes. Jewelry typically uses plating to give a silver or gold finish. Objects can be plated with films as thin as a single atom, so plating finds uses in nanotechnology.
There are several plating methods, and many variations. In one method, a solid surface is covered with a metal sheet, and then heat and pressure are applied to fuse them (a version of this is Sheffield plate). Electroplating is a very common method.