Abstract: The process parameters were designed by orthogonal experiment.Diamond coatings were synthesized by Hot Filament Chemical Vapor Deposition (HFCVD) and the scanning electron microscopy (SEM), rockwell hardness tester, X-ray diffraction (XRD) were used to test the coating properties and cutting tests to determine the optimum carbon source concentration, deposition pressure and hot wire/substrate spacing for the micro and nano layers.The results show that the optimum micro-diamond coating deposition process parameters are carbon source concentration of 2;, deposition pressure 3 kPa, hot wire/substrate spacing 5 mm.The optimum nano-diamond coating deposition process parameters are Carbon source concentration of 5;, deposition pressure 5 kPa, hot wire/substrate spacing 8 mm.

Key words: The process parameters were designed by orthogonal experiment.Diamond coatings were synthesized by Hot Filament Chemical Vapor Deposition (HFCVD) and the scanning electron microscopy (SEM), rockwell hardness tester, X-ray diffraction (XRD) were used to test the coating properties and cutting tests to determine the optimum carbon source concentration, deposition pressure and hot wire/substrate spacing for the micro and nano layers.The results show that the optimum micro-diamond coating deposition process parameters are carbon source concentration of 2;, deposition pressure 3 kPa, hot wire/substrate spacing 5 mm.The optimum nano-diamond coating deposition process parameters are Carbon source concentration of 5;, deposition pressure 5 kPa, hot wire/substrate spacing 8 mm.