New set up for diamond coatings deposition in AC glow discharge plasma on WC-Co milling cutters of complex shape

In the current work, we developed a new type of CVD reactor for high-speed deposition of uniform diamond coatings on WC-Co milling cutters in AC glow discharge plasma with two plasma channels in the Ar/H ₂ /CH ₄ atmosphere. This CVD system successfully allowed one to deposit well-adherent MCD, UNCD and Multilayer diamond coatings with a thickness up to 60 μm on WC-Co milling cutters of various geometries and with a diameter up to 14 mm. We found that to minimize the edge effect, the optimal energy input for each plasma cord should be set in the range of 1.4–2.5 kW. We also found that diluting the H ₂ /CH ₄ atmosphere with argon in the range of 45–80% vol. is one of the necessary conditions to control the deposition process. Diamond deposition rate has been achieved up to 2.5–3 μm/h with a uniformity of deposition over 50% from maximum thickness. Presented CVD system is very promising due to sufficiently high deposition rate and ease of implementation, and it also has great potential for industrial scaling.