Metallic coatings have a wide range of uses besides aesthetic appearances. In the industrial world, a properly applied metal surface can make a stronger tool with less abrasion. Less abrasion will normally mean a longer lasting tool or surface. Metallizing a part or tool can also protect against corrosion from high humidity or chemicals. This is because the coating provides a thin layer of film which acts as a vapor barrier.
Chrome and electroplating have been common forms of providing a metal skin to a product. But in recent years another method has gained popularity. The process is referred to as physical vapor deposition, or PVD. In this method, the part to be coated is placed in a vacuum chamber. The part to be coated as the process will allow adhesion to a large number of non metallic sub-surfaces.
The coating is vaporized in the chamber by one of several methods, including electrical arc, pulsed laser electron beam plasma or high heat. The vaporized metal then attaches itself to the product and returns to a solid state. The result is a thin film of metal, usually only 1 to 2 microns in thickness. A number of metals are suitable for the coating material, including aluminum, chromium, titanium and zirconium.
A form of equipment used for one of the processes is referred to as a thermal evaporation. This equipment heats the coating material past its melting point to create a vapor cloud or vapor stream. The vapor then attaches itself to the product in the chamber. It is generally a less expensive process and can be used to apply reflective coatings for aesthetic effect.
The automotive, aircraft, medical and tool and die industries utilize PVD technology. For the aircraft industry, parts are often coated to lower the friction coefficient of outer components. The automotive industry takes advantage of PVD for headlights. It coats both the lens and the reflector portion of these parts. Tool and die manufacturers coat their products for less friction and corrosion protection. In the medical field, instruments are often given a PVD coating.