Diamond-like carbon coating (DLC)

Table of contents

• Diamond-like carbon coating (DLC)
• What is diamond-like carbon coating?
• DLC coating properties at a glance
• Types of DLC coatings
• How DLC coatings are deposited
• Applications of diamond-like carbon coatings
• DLC coating systems & integration from Novel-Tec
• FAQ

Diamond-like carbon coating (DLC)

What is diamond-like carbon coating?

Diamond-like carbon coating is a thin amorphous carbon film that combines some of the hardness and low friction of diamonds with the smoothness and chemical stability needed for industrial and medical parts. A DLC coating is typically a few hundred nanometers to a few micrometers thick and is applied to a substrate to improve wear resistance, reduce friction and protect against corrosion without changing the dimensions of the component in any relevant way. As a functional layer, DLC belongs to the broader field of thin film deposition, where film structure, adhesion and uniformity define the final performance.

The properties of a DLC coating depend on its carbon bonding structure, particularly the ratio of diamond-like (sp³) to graphite-like (sp²) bonds, and on whether hydrogen or other elements are added. By adjusting these factors during deposition, the same base technology can produce coatings ranging from soft and lubricating to extremely hard and wear-resistant. In practice, this means a single coating family can be tuned for very different goals, from low-friction surfaces to highly wear-resistant protection.

DLC coating properties at a glance

Diamond-like-carbon coatings stand out because they bring together properties that are usually hard to combine in a single layer, such as high hardness together with low friction. The exact values depend on the DLC type, the deposition method and the process parameters, so the ranges below should be read as typical guidance rather than fixed numbers.

Property	Typical range / behaviour
Hardness	Roughly 1,000 to 5,000 HV, depending on type (a-C:H to ta-C)
Coefficient of friction	Low, often around 0.05 to 0.2 against steel in dry conditions
Coating thickness	A few hundred nm up to several µm
Wear resistance	High, strongly reduces abrasive and adhesive wear
Corrosion protection	Good chemical inertness, acts as a dense barrier layer
Temperature stability	Stable up to roughly 300 to 400 °C, type dependent
Deposition temperature	Low to moderate, suitable for many sensitive substrates
Biocompatibility	Good for selected medical and implant applications
Surface finish	Smooth, low roughness, replicates the substrate surface

The combination of a hard, low-friction surface with good chemical stability is the main reason DLC is chosen over standard hard coatings in demanding applications. Which specific balance of properties you get depends on the type of DLC, which is covered in the next section.

Types of DLC coatings

DLC is not a single material but a family of carbon coatings. The main difference lies in the bonding structure and whether hydrogen or other elements are added, which decides how hard, smooth, or wear-resistant the final layer is.

Type	Key feature	Typical use
a-C:H (hydrogenated)	Lower internal stress, smooth and low friction	Sliding parts, components, general wear protection
ta-C (hydrogen-free)	Highest hardness and wear resistance	Cutting tools, heavily loaded surfaces
Doped / metal-containing DLC	Tuned conductivity, stress or adhesion	Sensors, electrical contacts, special substrates

The right type depends on the load, the substrate and the function the coating has to fulfill. The choice of type also influences which deposition method is most suitable, which is covered next.

How DLC coatings are deposited

DLC coatings are produced in a vacuum process where carbon is deposited onto the substrate atom by atom. The two methods most relevant for industrial DLC are plasma-enhanced chemical vapour deposition (PECVD) and sputtering as part of the broader PVD family. Both run at low to moderate temperatures, which keeps sensitive substrates safe.

• PECVD: A carbon-containing gas is broken up in a plasma and forms a hydrogenated DLC layer. Well suited for smooth, low-friction films on complex shapes.
• Sputtering / PVD: Carbon is released from a solid target and deposited on the substrate, often used for harder, hydrogen-free layers and for doped DLC.

Good adhesion is critical for DLC, so the substrate is usually cleaned and activated before coating, fpr example, with a plasma pre-treatment, and an interlayer is often added to bond the film to the part. Film thickness, uniformity and stress are controlled through process pressure, power and substrate handling.

Applications of diamond-like carbon coatings

Because DLC combines hardness, low friction and chemical stability, it is used wherever parts have to last longer, run smoother, or stay clean under demanding conditions.

Optics, sensors and electronics

DLC serves as a protective and functional layer where smooth surfaces and stable properties are essential, for example, in semiconductor and sensor components. Doped variants can also provide tuned electrical behavior for specialized applications.

Medical devices

In medical technology, DLC is valued for being biocompatible, smooth and highly wear resistant. It is applied to implants, surgical instruments and diagnostic components to reduce friction and improve corrosion resistance.

Tooling and precision parts

Cutting tools, molds and machine components benefit from the high hardness and low friction of DLC. The coating reduces wear and extends tool life, which keeps tolerances stable over longer production runs.

Aerospace and energy

DLC supports precision and moving components that operate under high loads or in demanding environments. Its combination of wear and corrosion resistance helps protect parts where reliability is critical and maintenance is difficult.

DLC coating systems & integration from Novel-Tec

Novel-Tec helps customers bring IntlVac DLC coating into their own production. We do coat parts as a service but select, configure and integrate the right deposition system for your substrate, DLC type and throughput. Because DLC stands or falls with adhesion and film stress, we pay particular attention to surface pre-treatment and interlayers so the coating bonds reliably instead of delaminating under load.

Active in semiconductors and high-tech equipment for over 30 years, we work with established partners to build systems around your process. For DLC, we rely on systems from our partner Intlvac, such as the Aegis DLC platform, and configure them to match your substrate, DLC type and throughput. Targets such as hardness, uniformity and adhesion are defined up front and verified together during acceptance, and every system is backed by technical service covering maintenance, repairs, spare parts and upgrades, with on-site response usually within 24 to 48 hours.

FAQ

Is DLC the same as diamond?

No. DLC shares some properties with diamond, such as high hardness and low friction, but it is an amorphous carbon film, not a crystalline diamond. It delivers diamond-like performance at a fraction of the cost and can be applied as a thin coating on existing parts.

How long does a DLC coating last?

The lifetime depends on the load, the substrate and the application. Under suitable conditions, a DLC coating can last for the full service life of a component, since it strongly reduces wear and friction. Poor adhesion or the wrong DLC type for the load are the most common reasons for early failure.

Can Diamond-like carbon coating be applied to any material?

Most metals, hard alloys and many ceramics can be coated, provided they tolerate the process temperature and are properly prepared. Adhesion often depends on a suitable interlayer between the substrate and the DLC film. Very soft or heat-sensitive materials may need a specific low-temperature process.

Does DLC change the dimensions of a part?

Not in any relevant way. A DLC coating is only a few hundred nanometers to a few micrometers thick, so it follows the existing geometry without altering tolerances. This makes it well suited for precision components.