Applying PVD coatings to various products can add value by improving their appearance, performance, or both. The driving force for using PVD coatings is technical and/or economic limitations to manufacturing components entirely of a single material with all desired characteristics. That being the case, product design, including material selection, requires considering: application, the environment where the product will be used, cost of raw materials, manufacturing costs, final price to the customer, etc.
PVD coatings allow you to use base materials (aka – substrate) that address most of the product’s engineering needs and cost constraints by adding a protective, cosmetically appealing layer to the final manufactured part or tool.
Learn more about PVD coating durability below.
Manufacturers often ask us about PVD coating durability. Some of the most common questions are:
- How long does a PVD coating last?
- Does a PVD coating wear off?
- What is a typical PVD coating thickness?
- What if the PVD-coated product is exposed to harsh “chemical” environments?
- How durable is a PVD coating?
How long does a PVD coating last?
The ability of a PVD coating to remain functional and retain its cosmetic appearance depends on several factors:
- Coating material
- Coating thickness
- Adhesion between coating and substrate
- Type and hardness of the substrate
Zirconium, titanium, and chromium are the base materials of choice for most decorative and performance coatings. When combined with nitrogen, carbon, and/or oxygen in the PVD process, these materials can produce a wide range of colors and achieve very high hardness, protecting against wear with an excellent cosmetic appearance.
PVD coating thickness
For comparison, high-quality tool steel used in drill bits has a hardness of around 1000 Vickers; the hardness of zirconium nitride (ZrN), for example, is typically about 2500-2700 Vickers.
Therefore, in decorative applications with mild to moderate wear, coatings a few tenths of micrometer (0.2 to 0.5μm) thick can withstand many years of use without significant wear.
For products that endure harsher wear conditions, not only does the selection of the coating material and thickness (typically >1μm) need to be considered, but the substrate should be harder to provide support to the coating. That is the case because, as it is very thin, the coating can deflect to the fracture point if the substrate yields under localized pressure in a stress situation. If using a product may expose it to gouging, for example, harder substrates and thicker PVD coatings are recommended.
How about PVD coating durability with exposure to harsh “chemical” environments? Does the PVD coating wear off?
Another aspect of durability is the resistance to environmental conditions such as corrosion and oxidation, i.e., chemical stability. Carbides, nitrides, and oxides of metals are generally more chemically inert than their pure metallic forms. This characteristic means that PVD coatings can provide years of tarnish-free appearance to consumer products such as faucets, door hardware, smart phones, etc. In the case of coatings used in tools, e.g., for machining, injection molding, punching applications, etc., wear resistance, and chemical stability are required. Choosing the correct coating can increase tool life and productivity by orders of magnitude.
- Durable PVD coatings add long-lasting protection while maintaining the product’s cosmetic appearance.
- The careful design of a product should include a proper selection of the core material and the type and thickness of the PVD coating.
- PVD coatings extend tool life (which may mean less maintenance and tool changes and reduced scrap). Actual cost savings due to improved durability will depend on the application and type of coating.
VaporTech systems give you durable PVD coatings in a variety of decorative finishes. We offer three right-sized VT-i Series machines suited for varied applications in many industries. Contact us today for more information about durable PVD coatings.