20.500.12556/RUL-106740 Effect of the slide-to-roll ratio and the contact kinematics on the elastohydrodynamic friction in diamond-like-carbon contacts with different wetting behaviours In this paper, we show how the slide-to-roll ratio (SRR), the contact kinematics and the surface energy all have important effects on the elastohydrodynamic friction. As reported previously, diamond-like-carbon (DLC) contacts of the type DLC/DLC provide the lowest coefficient of friction, in particular those DLC materials with the lowest surface energies (three different DLC coatings were used in this study). A friction reduction of up to 48 %, compared to a steel/steel contact, was obtained. A surprising new finding from this investigation is that the friction in DLC contacts is significantly reduced for high SRRs, i.e. a difference of up to 27 % was measured in the DLC/DLC contacts when the SRR increased from 0.5 (rolling prevails) to 1.8 (sliding prevails). However, even more surprising is the effect of the SRR on the friction in mixed steel/DLC contacts, which is related to the contact design and its kinematics. We found that if the DLC is coated on the slower surface, a high SRR will not reduce the friction to any significant extent, typically about 5 %, and at most 13 %, compared to steel/steel contacts. However, a significant friction reduction is observed when applying a low-surface-energy DLC coating to the faster surface-on average about 20 % and as high as 33 %. In this case (a high SRR and DLC on the faster surface), mixed steel/DLC surfaces can experience a very similar friction as that seen for DLC/DLC contacts. Qualitatively, the same behaviour was found for both positive and negative SRR values. EHD lubrication DLC surface energy wetting slide-to-roll ratio tribologija mazanje DLC prevleke true false true Angleški jezik Slovenski jezik Članek v reviji 2019-03-14 13:39:52 2019-03-14 13:39:54 2025-03-11 13:56:31 0000-00-00 00:00:00 2015 0 0 Str. 1-10 iss. 1 Vol. 60 Oct. 2015 0000-00-00 PostprintKoncna Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 2016-09-09 539.92(045) 1023-8883 10.1007/s11249-015-0593-3 14197019 2806555 RAZ_Polajnar_Marko_i2015.pdf RAZ_Polajnar_Marko_i2015.pdf 1 6ADAE8FCBC3CAD84897F59FDD2C2BE95 4312550adc8614c9535898589ab80e4b2e7151a23f3eb6f7c7b50551cf61eae9 5e175709-a1b6-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=117515 https://link.springer.com/article/10.1007%2Fs11249-015-0593-3 1 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=117514 Fakulteta za strojništvo 0 0 0