Sheffield Plating is created by the integration of silver and copper with a likely base metal. The approach was accidentally discovered by cutlery-maker Thomas Boulsover in 1743, while trying to heat and repair a decorative knife handle. He noticed that two metals behaved differently when heated then layered over one another. Subsequently he refined the process and the first industrial metal plating process was born. Since then, the seminal "Sheffield Process" has become widely accepted as a basic metallurgical tool for chrome-plated accessory products.
This process allows a thin secondary finish to be applied over a base material through the application of high temperature and vacuum delivery. The approach is sometimes referred to as hard coating. The heating process creates condensation, and this vaporized work product is impregnated within a base material by vacuum forming. Some of today's products include: chrome-plated automotive lug nuts, semiconductors, plastic bags, and hard coating for bits or blades for high-speed computer-controlled (CnC) cutting machines.
Sputter deposition is similar to the process for PVD production. However in this case the application of the secondary material is primarily applied by electronic means. Essentially a base material is charged with high energy, and a secondary materials layer is introduced to the original by vacuum forming. The process is highly specialized, although this chrome plating technology is one of the industrial mainstays for the custom automotive accessory segment.