How does PVD process work?

　　 PVD is also called Physical Vapor Deposition.But how does PVD process work?It is a process carried out under high vacuum and, in most cases, at temperatures between 150 and 500 °C.

　　In the PVD process the high purity, solid coating material (metals such as titanium, chromium and aluminium) is either evaporated by heat or by bombardment with ions (sputtering). At the same time, a reactive gas (e.g. nitrogen or a gas containing carbon) is added; it forms a compound with the metal vapour which is deposited on the tools or components as a thin, highly adherent coating. A uniform coating thickness is obtained by rotating the parts at a constant speed about several axes.