DLC coating

DLC coating is a vacuum-based surface finishing treatment applied to metallic workpieces by means of vaporisation. DLC stands for Diamond-Like Carbon and refers to the material that is evaporated during the process. DLC coatings are characterised by outstanding hardness and wear properties, and minimise friction even in dry conditions. These properties make them ideal for tribological machine elements and other assemblies with sliding and rolling movements. At Härtha, we have state-of-the-art technologies for DLC coating. We apply our wealth of experience to set the right parameters for the successful refinement of your workpieces. We look forward to hearing from you.

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The process

DLC coatings are diamond-like carbon coatings. There are various techniques available. The most common are PVD coating, a physical process, and plasma-assisted chemical deposition or Plasma-Assisted Chemical Vapour Deposition, "PACVD" for short.


The techniques are further categorised into hydrogen-containing, amorphous carbon coatings (Amorphous Diamond-Like Carbon, "ADLC" for short) and hydrogen-free coatings.


Hydrogenated amorphous carbon coating


ADLC coating is the most common variant of DLC coating. It is usually applied using the PACVD technique. These DLC coatings achieve hardness levels between 1,200 HV and 2,200 HV and dry friction values of 0.1 to 0.2 against metal. They can generally be applied at temperatures up to 300 °C.


The addition of doping elements makes it possible to adapt the properties of the coating to the desired outcomes.



Hydrogen-free DLC coatings


Hydrogen-free DLC coatings are usually harder than ADLC coatings, and have a very low coefficient of friction as well. They are usually applied to the workpiece by means of the arc-PVD technique. This procedure produces tetrahedral amorphous carbon (ta-C), which offers a higher abrasive wear resistance than amorphous carbon.


These particularly wear-resistant DLC coatings are often used in the industrial sector, for example for automotive components, racing vehicles, and industrial components, as well as for oil and petrol applications, camshafts, valves, hydraulic pumps, and much more.



PVD vs. PACVD processes


Coating process 



DLC coating 





Hardness HV 0.05 

1.200 – 1.800 

2.200 – 2.000 

Application temperature 

350 °C 

300 °C 

Deposition temperature 

< 200 °C 

< 200 °C 




Coating thickness µm



Friction coefficient

0.2 dry, against steel

0.1 dry, against steel

Suitable materials

The DLC coating takes place at very low temperatures (below 200 °C). The process is therefore equally suitable for refining aluminium, copper, brass or low-tempered steels. Some suitable materials at a glance:

  • Chrome
  • Steel
  • Aluminium
  • Copper
  • Titanium
  • Brass
  • Molybdenum
  • Silicon

Areas of application

DLC coatings are outstandingly suitable for protecting components that are exposed to high loads and extreme friction. They are used in fields such as the automotive industry, mechanical engineering, and the food industry. Typical applications are:

  • Hydraulic drives
  • Fuel injection systems
  • Pumps
  • Cutting blades
  • Filling plants


The low friction coefficient and the great hardness of DLC coatings protect the component against heavy wear, and thus against pitting, chafing and seizing. 

The advantages at a glance

  • Low coating temperature (up to 200 °C)
  • Very thin layer thickness (usually 1 μm – 6 µm)
  • Maximum application temperature of up to 350 °
  • High adhesive strength
  • Great dimensional stability
  • Microhardness up to 2,200 HV
  • High chemical resistance
  • Low coefficient of friction (0.08 – 0.1)
  • Low adhesion tendency
  • Corrosion protection
  • Visual refinement

Our processing options

Depending on your specific application, various coating systems may prove to be ideal for your workpieces. In addition to standardised PVD coatings, we also offer DLC coatings that are specially tailored to your needs.

Process locations

HÄRTHA operates various locations in Germany, Italy, and the Netherlands. Refer to our location overview to learn where we perform DLC coating, and which other processes we offer in your vicinity.

Customer information

Before we can quote you an offer for DLC coating, we require as a first step the material designation of the workpiece to be treated and, if applicable, information on any thermal pre-treatments.