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Nucleation and Growth of Diamond Films on Ni‐Cemented Tungsten Carbide: Effects of Substrate Pretreatments
Author(s) -
Polini Riccardo,
Marcheselli Giancarlo,
Traversa Enrico
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb07095.x
Subject(s) - diamond , materials science , nucleation , chemical vapor deposition , tungsten carbide , material properties of diamond , scanning electron microscope , chemical engineering , tungsten , raman spectroscopy , metallurgy , substrate (aquarium) , carbide , etching (microfabrication) , composite material , nanotechnology , chemistry , layer (electronics) , physics , oceanography , organic chemistry , optics , geology , engineering
The nucleation and growth of diamond films on Nicemented carbide is investigated. Substrates made of WC with 6 wt% of Ni were submitted to grinding, and then to different pretreatments (scratching, etching, and/or decarburization) before diamond deposition. Diamond synthesis was carried out by hot‐filament chemical vapor deposition (HFCVD) using a mixture of CH 4 (1% v/v) and H 2 . Depositions were performed for different lengths of time with the substrates at various temperatures. The specimens were analyzed before and after deposition by scanning electron microscopy (SEM), energy‐dispersive spectroscopy (EDS), and X‐ray diffractometry (XRD). Raman spectra showed that the phase purity of the diamond films was not affected by the presence of nickel on the substrate surface. After wet etching pretreatments, the nucleation of diamond was enhanced, mainly at the WC grain boundaries. Continuous films were obtained on scratched and etched substrates. The decarburizing treatment led to the formation of metallic tungsten and of brittle nicke–tungsten carbide phases. These phases reacted in the early stages of diamond film formation with gaseous carbon species with a parallel process which competes with stable diamond nucleus formation. The diamond film formed after long‐term deposition on these samples was not continuous.