Waxes, films and other liquid to solid materials have been used as a top coating for decades. For those seeking a metallic topcoat to their products, electroplating was the process of choice in the past.
But recently, refinement of a process called physical vapor deposition has gained a great deal of popularity among manufacturers. In PVD technology, a metallic substance, such as titanium, chromium and zirconium is taken to a vaporized state. This may accomplished with the use of a power electric cathodic arc. The product to be coated is placed in a vacuum chamber and the vaporized metal attaches to the product.
The vaporized metal will then attach to the targeted product. An inert gas may be then injected into the chamber to ionize the excess metallic vapor and eject it off the target product. The result of the process is a thin film metallic top coating that completely seals the targeted product.
The film is normally no more than 1.0-2.0 microns or about 1/10th the thickness of a human hair. Because the film is so thin, it has no more than a nominal effect on the dimensions of a product and will not affect normal operation. Depending on the metallic coating, the resulting coating provides good heat resistant properties, varying in heat protection from 900-1700 degrees Fahrenheit. With a heat and corrosion resistant coating, the useful life of the coated product can increase substantially.
Though electroplating remains a popular method to apply a metallic coating to a product, it requires a positive negative attraction for the method to succeed. This means the product to be coated must have electrical conductive properties. In PVD coatings, there is no reliance on conductivity and the coating can be applied to a wider range of products, including plastic and glass.
Some companies have been refining the PVD process for the past 30 years and have applied the process to a wider range of products. Today, modern PVD coatings have been applied to optical equipment, tools, tool making dies, solar panels, computer components, aeronautical parts and surgical equipment. An increasingly popular use for a PVD coating is a protective film for firearms.