Dynamic evaluation of surface damage mode transitions in carbon nitride coatings due to sliding contact with a spherical diamond

摘要

The influences of both the nitrogen incorporation parameters and the coating thickness on the surface damage mode transitions in carbon nitride coatings have been initially studied from the view points of critical loads and critical groove depth. An environmental scanning electron microscope, in which a traditional pin-on-disk tribotester was installed, has dynamically provided direct evidence that when and how the surface damage mode transitions do occur during the room-temperature sliding of ion beam assisted carbon nitride coatings deposited on single crystal silicon substrates against a spherical diamond. At a controlled relative humidity of 40%, the normal loads of all sliding tests were consecutively changed until 300 mN at a sliding speed of 10 mm/s. Based on a detailed study of seven combinations of nitrogen incorporation parameters and five kinds of thicknesses, i.e., 0, 10, 50, 100 and 200 nm, carbon nitride coatings showed that the sliding mainly consisted of `No grooving', `Grooving without material removal' and `Grooving with material removal' three typical surface damage modes. The mode transitions were then experimentally studied in the light of critical loads and critical groove depth to the summarized surface damage modes and the influences of both the nitrogen incorporation parameters and the coating thickness were further discussed with a relation to nano-indentation hardness and internal stress.