Fraunhofer Institute for Surface Engineering and Thin Films IST
Tablet stamp coated with a SICON® DLC anti-adhesive coating for the release-agent-free production of effervescent tablets: Prevention of adhesion of the pressed material and wear protection.
Wear-resistant anti-adhesive coatings
Surfaces need to have good anti-adhesion properties in order to avoid deposits, contaminants, and adhesions or to meet demands for drop formation. In addition to low surface energy, the tools or components must also exhibit excellent wear resistance because of the heavy mechanical loads placed upon them. Hard coatings can possess not only high hardness but also anti-adhesion properties. Coatings consisting of modified diamond-like carbon (DLC), e. g. SICON® and also chromium nitride layers (CrN), are excellent examples for such a combination of properties.
Generation of highly cross-linked, low-adhesive coatings in the PACVD process
On the basis of the kinetic acceleration of the elements excited during the low-pressure deposition, particularly strongly cross-linked coatings can be produced. An optimal choice of the elements to be deposited can thereby simultaneously influence the functionality of the coating, as a result of which surfaces with a low adhesive property can be achieved. The utilization of this deposition process enables the production of wear-resistant, low-adhesive coatings which simultaneously exhibit a non-stick and easy-to-clean property.
Adhesion-resistant, easy-to-clean wear-resistant coatings for applications in manufacturing
The amorphous hydrocarbon coatings deposited by means of PACVD technology do not only protect against wear. In many applications, such as in the field of pharmaceutical process engineering or the processing of plastics and powders, additional properties are required which improve the manufacturing processes. At the Fraunhofer IST, we are able to achieve coatings which offer a very low adhesion tendency and the easy removal of contamination for your applications.
Please do not hesitate to contact us.
Properties and advantages
The wetting behavior can be varied in a defined way by modifying the DLC coatings with nonmetallic elements. The elements fluorine and silicon significantly reduce surface energy and thus wettability (e. g. F‑DLC, SICON®, SICAN). Nitrogen, boron and oxygen cause the opposite effect, i. e. the surfaces could be wetted easily (e. g. N-DLC, B-DLC). DLC coatings modified with silicon and oxygen have good anti-adhesion properties similar to Teflon®, but a significantly higher wear resistance and temperature stability. Chromium-based layer systems (CrN and variations) also show favorable anti-adhesion as well as good mechanical and tribological properties. By variations of the deposition process parameters it is possible to adjust layer composition, structure and property profile to customer-specific requirements.
DLC coated tool for tyre forming.