We Answer Your Questions About Diamond-Like Carbon Finishes

Although performance DLC coating applications such as engine parts or cutting tools are better-known, decorative DLC coatings are now popular with consumers in products ranging from watches to vehicle trim.

Unlike color PVD coatings, DLC coatings come in shades rather than colors, ranging from grays to gorgeous dark graphite. Customers deposit dark black finishes via a PVD rather than a DLC coating process, but consumers love the look of black DLC coating. Darker DLC coatings are as durable as metallic PVD coatings and retain a low coefficient of friction.

PVD coating comes in a wide range of natural metallic and other colors. DLC coating is limited to grays and blacks, providing the distinct DLC coating look consumers love. DLC coating must also be deposited at a somewhat higher thickness as it is a semi-transparent coating at thinner deposition levels.

Once we set a recipe, color variations are so slight that the naked eye can’t distinguish within-run and run-to-run variations.

DLC can coat most conductive metals. Substrate hardness and surface finish influence the durability of the coating. For hardness, a good analogy is ice on water: the chance of breakthrough decreases as the ice (i.e., hard coating) thickens over the softer water (i.e., substrate). Alternatively, as the substrate hardens, so does the “composite hardness” of the substrate and coating. This result applies to all thin films, including DLC coating and conventional PVD finishes. The base material strongly influences durability and varies with the end-use.

DLC is a semi-transparent coating. Therefore, DLC coating thickness determines the color of the DLC coating. For our standard applications, PVD coatings are thinner than 1 micron. DLC coating thickness is typically ≥1 micron, the point where the coating becomes opaque.

Typical DLC coating temperatures range from 100-250 C. Our DLC coating machines run in the 150-200 C range. Above those temperatures, the DLC coating may not form properly. The DLC coating thickness required to achieve opaque finishes makes maintaining part temperatures <125C challenging.

There’s a great deal of variation among brands, but all VaporTech® DLC coating machines give you PVD and DLC coating options at the click of the (recipe) button.

Our systems run the plasma-enhanced chemical vapor deposition (PE-CVD) process that creates DLC coatings via a chemical vapor deposition (CVD) process. Our hybrid VT-1500i™ system adds sputtering capability for metal-doped DLC coatings. For example, adding tungsten creates the VaporTech® W-DLC finish.

DLC coating is excellent at coating exterior product surfaces, and some internal dimensions can be coated. But DLC has limitations and can’t be used to coat deep recesses like the inside of tubes.

DLC coating cost varies greatly depending on whether you use a coating service or bring a DLC coating machine in-house. DLC coating costs approximately $20 per part when using a coating service. This option makes sense if you DLC coat a low volume of parts. However, running your DLC coating machine in-house brings per-part coating costs down, sometimes to less than $1 per part.