Our Multistep Sputtering and PACVD CertessTM Carbon DLC Process Enables Coating Properties to be Tailored to Provide Key Product Attributes
DLC (Diamond-Like Carbon) Coating involves a multistep process:
- Precleaning
- Placement of parts in a planetary fixture using single-, double- or triple-axis rotation
- Pump-down under vacuum
- Low-temperature preheating process
- Ion Bombardment
- Underlayer deposition (PVD process)
- Amorphous carbon layer deposition
- Cooling
Precleaning, Fixturing, Pump-down
After going through a multistep pre-cleaning process, the parts are placed on a planetary fixture capable of single, double or triple-axis rotation. The planetary fixture is then placed into the vacuum chamber and the chamber is evacuated and put under vacuum.
Preheating & Ion Bombardment
After the chamber reaches the preset vacuum level, low-temperature preheating begins. Next the product is bombarded with ions of argon gas to scrub or sputter-clean the surface and remove micro-oxides and micro-contamination. This scrubbing of the surface improves the adhesion of the coating to the substrate.
Underlayer Deposition (PVD Coating)
The first step in the coating process is to deposit an underlayer using a high-energy PVD sputtering process developed by the HEF Group to deposit a dense, well adhered, smooth under layer.
The DLC coatings will usually include several layers of different materials as an underlayer, such as Cr, CrN, W, WC-C or Si, with a top layer of amorphous carbon, with hydrogen. The selection of the underlayer is based upon several factors, such as: adhesion requirements, wear and contact modes, friction regimes encountered during operation, load-carrying capacity, and other metallurgical considerations.
Amorphous Carbon DLC Deposition
As the underlayer coating reaches the proper thickness, the process transitions into the DLC coating step which deposits a dense, smooth, amorphous carbon hydrogenated (a-C:H) layer onto the product’s surface. The amorphous carbon DLC layer has the unique combination of high hardness and low friction coefficient, yielding the hardness of diamond and the lubricity of graphite. The properties can be tailored to an application depending on:
- Deposition technology & parameters
- Alloying elements
- Coating architecture (single, multilayered, or graded)
