Smart DLC coating top coating for reduction of counter surface wear in fuel contact
2012 (English)In: Faraday Discussion 156: Tribology, 2012Conference paper, Poster (Refereed)
Place, publisher, year, edition, pages
Research subject Engineering Science with specialization in Materials Science; Engineering Science with specialization in Tribo Materials
IdentifiersURN: urn:nbn:se:uu:diva-182046OAI: oai:DiVA.org:uu-182046DiVA: diva2:558267
Faraday Discussion 156: Tribology
There is a continuous strive towards reducing energy consumption and increasing lifetime of components. Together with environmental impacts these are today very important factors when designing new tribological systems for automotive applications.
Many heavy-duty components or particularly exposed surfaces are coated with diamond like carbon (DLC) for protection and to improve the overall tribological performance. These coatings are often seen as a homogenous group of hard amorphous carbon coatings, being chemically inert with great wear resistance in most lubricated environments. However, the composition and hardness may vary significantly between different DLC variants. Depending on the working atmosphere (oil, fuel) used, the coating behavior (i.e. friction and wear) may consequently vary. Therefore it has become more and more important to tailor the coating properties for specific applications.
A metal-doped DLC coating with several stacks of alternating layers of hydrogenated amorphous carbon and metal doped amorphous carbon has been developed in an attempt to combine low friction properties and improved wear behavior under lubricated conditions. The coating was deposited with PVD/PA-CVD with a Cr interlayer on mirror polished HSS substrates. A soft carbon top layer was added on top of the sequence for a smoother running-in behavior.
The coating was tested in a reciprocal sliding test rig, against a component steel counter surface with the contact wetted by fuel. The tests were performed at low speeds to operate in the boundary friction regime, where the coating is most needed. A variation of the same coating with just a single stack of the same layers, but without the soft top layer, was equally investigated for comparison.
Tests were run in several commercially available fuels and the main focus was on the friction behavior and the wear of the countersurface. Since DLC coatings normally have extremely low wear it is important to prepare coatings that also do not degrade the countersurface.
Results showed that the friction and wear behavior of both the different coatings and the countersurface varied significantly between the different fuels.2012-10-022012-10-022016-04-20