Mechanisms of time-modulated polarized nano-crystalline diamond growth
Langue
en
Article de revue
Ce document a été publié dans
Surface and Coatings Technology. 2013, vol. 222, p. 97-103
Elsevier
Résumé en anglais
Two bilayer systems (TaN/Mo and ZrN/Mo) have been deposited onto WC-Co cermets in order to limit the cobalt diffusion from this substrate and to promote the diamond nucleation. Mo was the top layer. The diamond CVD coating ...Lire la suite >
Two bilayer systems (TaN/Mo and ZrN/Mo) have been deposited onto WC-Co cermets in order to limit the cobalt diffusion from this substrate and to promote the diamond nucleation. Mo was the top layer. The diamond CVD coating process includes two steps: 1) Bias Enhance Nucleation (BEN) step for diamond nucleation control, 2) diamond growth step with a time-modulated negative substrate polarization to form nanocrystalline diamond grains (NCD). Original cluster morphology of diamond film was obtained, and patented under the name PyrNCD (for pyramidal NCD). Clusters are multilayered and composed of two diamond layers (resp. grain sizes: about 1 nm and 10 nm) periodically repeated. Thermomechanical computations have been carried out to understand the stress distribution inside the multilayer systems before and after diamond deposition. Computation results demonstrate that the architecture of the system is optimized and the morphology of PyrNCD diamond clusters should not degrade their substrate adhesion. A mechanism for the formation of the diamond layer is proposed for a time-modulated polarized diamond growth process to understand the formation of both the specific morphology and the NCD grains.< Réduire
Mots clés en anglais
NCD
Time-modulated biased diamond
Multilayer systems
Carbon diffusion
Diamond growth mechanism
Tooling applications
Origine
Importé de halUnités de recherche