Deposition in Microwave Plasma and Performance of Polycrystalline Diamond Coatings with High Adhesion on Sialon Ceramics Cutting Tools

A technology for reducing the friction of SiAlON cutting ceramics by coating with diamond by means of microwave plasma chemical vapor deposition is proposed. Using the scratch test method, it was found that the friction coefficients of the initial SiAlON substrates decreased by 8.3–6.3 times as compared to those coated with diamond, namely to 0.04–0.07. Microwave configuration control and edge elimination in the ARDIS-100 chemical vapor deposition reactor provide a uniform cutting edge at the border of the substrate and diamond coating. The use of a specially designed substrate holder and the deposition of a multilayer silicon carbide / microcrystalline diamond / nanocrystalline diamond film ensure a strong adhesion of the diamond to the SiAlON substrates. The possibility of growing diamond from microwave plasma on a group of substrates in one run is demonstrated. The critical loads of the diamond coating adhesion to the SiAlON substrates, according to the scratch tests have exceeded 41 N.