1- کلیاتی درباره فناوری PVD:
Physical vapor deposition (PVD) describes a variety of vacuum deposition methods which can be used to produce thin films. PVD uses physical process (such as heating or sputtering)
to produce a vapor of material, which is then deposited on the object
which requires coating. PVD is used in the manufacture of items which
require thin films for mechanical, optical, chemical or electronic functions.
2- تکنیکهای موجود روش PVD:
- Cathodic Arc Deposition: In which 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: In which 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: In which the material to be deposited is heated to a high vapor pressure by electrical resistance heating in "high" vacuum.
- Pulsed laser deposition: In which a high-power laser ablates material from the target into a vapor.
- Sputter deposition: In which a glow plasma discharge (usually localized around the "target" by a magnet) bombards the material sputtering some away as a vapor for subsequent deposition.
3- مزایا فناوری PVD:
- PVD coatings are sometimes harder and more corrosion resistant than coatings applied by the electroplating process. Most coatings have high temperature and good impact strength, excellent abrasion resistance and are so durable that protective topcoats are almost never necessary.
- 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.
- More environmentally friendly than traditional coating processes such as electroplating and painting.
- More than one technique can be used to deposit a given film.
4- معایب فناوری PVD:
- Specific technologies can impose constraints; for example, line-of-sight transfer is typical of most PVD coating techniques, however there are methods that allow full coverage of complex geometries.
- Some PVD technologies typically operate at very high temperatures and vacuums, requiring special attention by operating personnel.
- Requires a cooling water system to dissipate large heat loads.