Nano-Scale Fatigue Wear of Carbon Nitride Coatings: Part I—Wear Properties

This paper, the first of two companion papers, reports empirical data on wear properties in carbon nitride coatings by a spherical diamond counter-face in repeated sliding contacts through in situ examination and post-sliding observation, with an emphasis on the effects of friction cycles and normal load. In the repeated sliding, a specific wear amount of about $10−9mm3/Nm$ was observed on the wear track of the carbon nitride coating when no wear particles were detected. On the other hand, a specific wear amount of about $10−6mm3/Nm$ was observed on the wear track of the carbon nitride coating, where wear particles were generated after a certain number of friction cycles. Wear rate change corresponds to a wear mode change. From in situ examination, the critical number of friction cycles, Nc, for wear particle generation is proven to be related to a wear mode change.