Enhanced tribological performances of nanocrystalline diamond film

Abstract

Diamond films are well known for their outstanding properties such as high hardness, possible low coefficient of friction, high thermal conductivity, excellent biocompatibility and electrical insulation. Diamond films with nanocrystalline grains (grain sizes between 3 and 15 nm) offer further advantages of low compressive stress, low surface roughness, and high amount of surface atoms in relation to volume leading to enhanced surface properties. In view of these, the present investigation is undertaken to explore the possibility of using nanocrystalline diamond (NCD) films in advanced automotive equipment. Accordingly NCD-films have been deposited using a modified hot-filament technique. Tribological behaviour of these films has been evaluated by means of a reciprocating model tribometer with different lubricant qualities. The worn surfaces were examined using scanning electron microscopy (SEM) and 3D white light confocal microscopy. The results show the influences of coating qualities and test conditions on the tribological response. Comparable friction coefficient can be found with high treated and low treated lubricants. These films exhibited negligible wear for the range of load tested.