Growth features of micro- and nanocrystalline diamond films on rotating high-aspect substrates

As a result of E-field modeling (COMSOL Multiphysical), the functions of the main conducting platform of the microwave reactor were expanded by combining it with a ring-shaped evanescent waveguide that ensures substrate rotation. In this geometry, twelve-layer micro- and nanocrystalline diamond films were deposited on a four-tooth end mill $\varnothing$ 12mm made of VK-6 alloy (WC+6%Co). The temperature regime of uniform heating of the milling cutter during rotation was determined. The structure, chemical and phase composition of the substrate and the synthesized coating were studied using scanning electron microscopy, X-ray fluorescence analysis and Raman spectroscopy in areas equidistant from the end of the cutter with a step of 5mm over a length of 25mm. The proposed geometry of the microwave path of the reactor ensured a favorable concentration of the E-field and uniformity of the temperature in the substrate area. Data on grain sizes and line intensities of diamond and ordered graphite demonstrate both uniformity of the diamond film thickness and an increase in the proportion of microcrystalline diamond compared to nanocrystalline diamond with distance from the end. It is shown that the coating at all points is under elastic compressive stresses increasing from the cutter tip from 0.7 GPa at the end to 1.2 GPa at a distance of 30 mm, reaching a maximum value of 3.1 GPa at a distance of 20 mm.