Physical vapour deposition (PVD) is a thin-film coating process which produces coatings of pure metals, metallic alloys and ceramics, thickness usually in the range 1 to 10µm. It is characterized by a process in which the material goes from a condensed phase to a vapor phase and then back to a thin film condensed phase. Physical vapour deposition processes are pollution free and normally use inorganic elements or compounds and gases.
The advantages and disadvantages of the PVD processes.
|1. Compared to the substrate materials, materials can be deposited with improved properties.|
2. Almost any type of inorganic materials can be used as well as some kinds of organic materials.
3. The processes are more environmentally friendly than processes such as electroplating.
|1. It is extremely difficult to coat undercuts and similar surface features.|
2. High capital cost.
3. Some processes operate at high technical requirements, such as high vacuums, high temperatures and appropriate cooling systems.
4. The rate of coating deposition is quite slow.
The most commonly used PVD processes are thermal evaporation, sputtering, and ion plating.
|Type||Thermal Evaporation||Sputtering||Ion Plating|
|Undertaken Environment||a controlled atmosphere at reduced pressure||a controlled atmosphere at reduced pressure||a controlled atmosphere at reduced pressure|
|Principle||Heating and condenses||The electrical generation of a plasma||A combination of thermal evaporation and sputtering|
PVD is used in a variety of applications, including:
1. Electronic Circuitry: aluminium tracks and ceramic resistors
2. Optics: anti-reflective ceramic coatings
3. Plastics: decorative coatings
4. Machine and press tools: prevention coatings