SURFACE COATING BY PHYSICAL VAPOR DEPOSITION
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Overview: | Physical
Vapor Deposition (PVD) comprises a group of surface coating technologies
used for decorative coating, tool coating, and other
equipment coating applications. It is fundamentally a vaporization coating
process in which the basic mechanism is an atom by atom transfer of
material from the solid phase to the vapor phase and back to the solid phase,
gradually building a film on the surface to be coated. In the case of
reactive deposition, the depositing material reacts with a gaseous environment
of co-deposited material to form a film of compound material, such
as a nitride, oxide, carbide or carbonitride. There are three basic process categories considered as PVD technologies: ion plating, evaporation, and sputtering. All utilize the same three fundamental steps to develop a coating. Each of the PVD technologies generate and deposit material in a somewhat different manner, requiring equipment unique to each process. The three fundamental steps include: 1. Vapor phase generation from coating material stock by -
2. The transfer
of the vapor phase from source to substrate by -
3. Deposition and
film growth on the substrate
PVD is a desirable
alternative to electroplating and possibly some painting applications.
PVD can be applied using a wide variety of materials to
coat an equally diverse number of substrates using any of the three basic
PVD technologies to deposit a number of desired finishes of variable
thickness with specific characteristics.
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Compliance Benefit: |
PVD is a desirable alternative to
electroplating and possibly some painting applications because it generates
less hazardous waste and uses less hazardous materials (i.e., no
plating baths). The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.
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Materials Compatibility: |
PVD coating processes are compatible with most metals and some plastics either as coatings or as substrates. However, temperature constraints may limit the degree to which dense coatings can be deposited on some plastics. Finally, PVD processes do not normally produce the kind of coatings that work well where lubrication is required. Thus, PVD coatings are not usually good choices for parts such as fasteners.
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Safety and Health: |
The safety and health
issues must be evaluated on a case-by-case basis. |
Benefits: |
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Disadvantages: |
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Economic Analysis: |
Economic considerations are probably the primary hindrance preventing conversion of plating operations to vapor deposition processes. A rough estimate of the capital cost for a new vapor deposition installation is several hundred thousand dollars. Operating costs are roughly equal to electroplating, although plating can be slightly less labor intensive.
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NSN/MSDS: | None identified.
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Approving Authority: |
Appropriate authority for making process
changes should always be sought and obtained prior to procuring or implementing any of the
technologies identified herein.
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Points of Contact: | For more information
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Vendors: | This is not meant to be a complete list, as there may be other suppliers of this type of equipment. PVD
Product and Services Directory
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Sources: | ASM Handbook, Vol. 5. Surface Engineering, ASM International, 1994. |