Publications Repository - Gdańsk University of Technology

Tribological properties of ultrananocrystalline diamond nanowall (UNCD NW) films were investigated quantitatively in three different and controlled tribo-environmental conditions, proposing the passivation and graphitization mechanisms. However, these mechanisms are rather complicated and possibly can be understood in well-controlled tribological conditions. It was shown that the friction and wear of these films were high in highPage 1 of 40 ACS Paragon Plus Environment The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 vacuum and room temperature (HV-RT) tribo-condition in which the passivation of carbon dangling bonds was restricted and frictional shear-induced transformation of sp3 carbon into amorphous carbon (a-C) and tetrahedral amorphous carbon (t-aC) was noticed. However, the friction coefficient was reduced to the ultralow value in ambient atmospheric and room temperature (AA-RT) tribo-condition. Here, both passivation of dangling bonds through atmospheric water vapor and graphitization of the contact interfaces were energetically favorable mechanisms. Furthermore, the conversion of diamond sp3 into hydrogenated-graphitized phase was dominating mechanism for observed super-low friction coefficient and ultra-high wear resistance of films in high-vacuum and high-temperature (HV-HT) tribo-condition. These mechanisms were comprehensively investigated by micro-Raman and X-ray photoelectron spectroscopy analyses of the sliding interfaces.

Authors

• Revati Rani,
• Kalpataru Panda,
• Niranjan Kumar,
• Sankaran Kamatchi,
• Ramanathaswamy Pandian,
• dr inż. Mateusz Ficek link open in new tab ,
• dr hab. inż. Robert Bogdanowicz link open in new tab ,
• Ken Haenen,
• prof. I-Nan Lin