Cobalt diffusion in different microstructured WC-Co substrates during diamond chemical vapor deposition

Abstract

Our investigation on diamond deposition using cemented tungsten carbide (WC-Co) has shown that diamond particles deposit at different rates onto micrograin and coarse-grain WC-Co substrates. Diamond deposition was carried out using a parallel-plate plasma-enhanced chemical vapor deposition system, which utilized the bias-enhanced growth (BEG) process. BEG was performed at four different times: 15, 20, 25, and 30 min. The resultant diamond-based deposits were characterized for morphology, microstructure, and crystallinity using scanning electron microscopy. It was found that diamond nucleation initiated at the grain boundaries of the substrates. The present article discusses the possible reasons that can potentially explain our key findings. In particular, the CO diffusion from the bulk material through the grain boundaries and onto the substrate surface using a theoretical approach.

Gradation Process by Imbibition in WC-Co for Mining Tools Application

“…The corresponding map clearly shows the presence of a hardness gradient, parallel to the lower surface (from 1315 to 1480 HV) which corresponds to a Co gradient (from 9 to 13 % wt Co) as demonstrated by the composition profiles of Figure 5. This result supports the conclusion established earlier by several authors [7,8] that the binder phase of the WC-Co cutter migrates in the diamond compacted powder during the HPHT process and makes the sintering of the diamond table easier.…”

Cobalt out‐diffusion and carbon phase composition at the WC‐10%Co/diamond film interface investigated by XPS, SEM, Raman and SIMS

“…Detection of cobalt XP peaks after a long CVD process of 360 min (Fig. 2a), for which a ∼4 µm thick film is grown, is indicative of cobalt's out diffusion during diamond formation 26. To quantitatively evaluate the content of cobalt in the diamond film after CVD process, the atomic concentration was extracted from the integrated area of the XP peaks of the components at the diamond film surface ( i.e .…”