Physical vapor deposition

• Cathodic arc deposition: A high-power electric arc discharged at the target (source) material blasts away some into highly ionized vapor to be deposited onto the workpiece. • Electron-beam physical vapor deposition: The material to be deposited is heated to a high vapor pressure by electron bombardment in "high" vacuum and is transported by diffusion to be deposited by condensation on the (cooler) workpiece. • Evaporative deposition: The material to be deposited is heated to a high vapor pressure by electrical resistance heating in "high" vacuum. • Close-space sublimation: The material and substrate are placed close to one another and radiatively heated. • Pulsed laser deposition: A high-power laser ablates material from the target into a vapor. • Thermal laser epitaxy: A continuous-wave laser evaporates individual, free-standing elemental sources which then condense upon a substrate. • Sputter deposition: A glow discharge (usually localized around the target by a magnet) bombards the material, sputtering some away as a vapor for subsequent deposition. • Pulsed electron deposition: A highly energetic pulsed electron beam ablates material from the target, generating a plasma stream under nonequilibrium conditions. • Sublimation sandwich method: This method is used for growing crystals such as silicon carbide (SiC). Metrics and testing Various techniques to characterize thin films can be used to measure the physical properties of PVD coatings, such as: • Calo testing: measures coating thickness • Nanoindentation: measures hardness of thin-film coatings • Pin-on-disc testing: measures wear and friction coefficient • Scratch testing: measures coating adhesion • X-ray micro-analysis measures structural features and heterogeneity of elemental composition of the growth surfaces == Comparison to other deposition techniques ==

Advantages • PVD coatings are sometimes harder and more corrosion-resistant than coatings applied by electroplating processes. Most coatings have high temperature and good impact strength, excellent abrasion resistance and are so durable that protective topcoats are rarely necessary. • PVD coatings have the ability to utilize virtually any type of inorganic and some organic coating materials on an equally diverse group of substrates and surfaces using a wide variety of finishes. • PVD processes are often more environmentally friendly than traditional coating processes such as electroplating and painting. • More than one technique can be used to deposit a given film. • PVD can be performed at lower temperatures compared to chemical vapor deposition (CVD) and other thermal processes. This makes it suitable for coating temperature-sensitive substrates, such as plastics and certain metals, without causing damage or deformation. • PVD technologies can be scaled from small laboratory setups to large industrial systems, offering flexibility for different production volumes and sizes. This scalability makes it accessible for both research and commercial applications. Disadvantages • Specific technologies can impose constraints; for example, the line-of-sight transfer is typical of most PVD coating techniques, however, some methods allow full coverage of complex geometries. • Some PVD technologies operate at high temperatures and vacuums, requiring special attention by operating personnel and sometimes a cooling water system to dissipate large heat loads. == Applications ==

Anisotropic glasses PVD can be used as an application to make anisotropic glasses of low molecular weight for organic semiconductors. The parameter needed to allow the formation of this type of glass is molecular mobility and anisotropic structure at the free surface of the glass. Cutting tools PVD is used to enhance the wear resistance of steel cutting tools' surfaces and decrease the risk of adhesion and sticking between tools and a workpiece. This includes tools used in metalworking or plastic injection molding. The coating is typically a thin ceramic layer less than 4 μm that has very high hardness and low friction. It is necessary to have high hardness of workpieces to ensure dimensional stability of coating to avoid brittling. It is possible to combine PVD with a plasma nitriding treatment of steel to increase the load bearing capacity of the coating. Chromium nitride (CrN), titanium nitride (TiN), and titanium carbonitride (TiCN) may be used for PVD coating for plastic molding dies. Other applications PVD coatings are generally used to improve hardness, increase wear resistance, and prevent oxidation. They can also be used for aesthetic purposes. Thus, such coatings are used in a wide range of applications, such as: • Aerospace industry • Architectural ironmongery, panels, and sheets • Automotive industry • Dyes and molds • Firearms • Optics • Watches • Jewelry ==See also==