Applying PVD coatings to various products can add value by improving their appearance, performance, or both. The driving force for using PVD coatings is the technical and/or economic limitations of manufacturing components entirely from a single material with all desired characteristics. That being the case, product design, including material selection, requires consideration of factors such as the application, the environment in which the product is used, the cost of raw materials, manufacturing costs, and the final price to the customer, among others.
PVD coatings enable you to use base materials (also known as substrates) 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.
Manufacturers often ask us about PVD coating durability. Some of the most common questions are:
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.
The ability of a PVD coating to remain functional and retain its cosmetic appearance depends on several factors:
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 a 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.
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, smartphones, 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.
VaporTech systems deposit durable PVD coatings for decorative and functional finishes. To meet your durability needs, we offer three right-sized VT-i Series™ machines and the new V.MAX1500™industrial coating system. Contact us today for more information about our coatings and coating equipment.