Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Hot Filament Chemical Vapour Deposition on Tungsten Carbide Milling Tools with Magnetic Field Assistance

Fung Ming Kwok1, Wai Sze Yip1 and Suet To1,a

1State Key Laboratory in Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong


Microcrystalline diamond (MCD) is the common diamond coatings applied to manufacturing tools that are used to machine difficult-to-cut materials. The coating layer is typically produced through hot filament chemical vapor deposition (HFCVD). In order to improve the growth rate as well as control the grain size of diamond particles which form coating layers on tungsten carbide milling tools, this study investigated deposition of the diamond film layers using conventional HFCVD machine design with the novel magnetic field assisted system. It was found that a magnetic field favoured the fabrication of smaller diamond grain of MCD and increased the growth rate of the diamond film. The characteristics of the diamond film on the milling tools were evaluated using SEM. The results showed that the cross-section of the diamond film reached to 3.25 µm with magnetic flux density of 100 mT, and 2.00 µm without magnetic flux density. The results show that the growth rate of the diamond film on the milling tools has been improved nearly 50% faster with magnetic field assistance. With the magnetic field assistance applied on the HFCVD machine, the grain size and the growth rate of diamond film can be controlled.

Keywords: Permanent magnetic field, Diamond coating, Thin films, Grain growth, Hot filament chemical vapor deposition

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