The optimization of the doping level of boron, silicon and nitrogen doped diamond film on Co-cemented tungsten carbide inserts

Boron doped, silicon doped and nitrogen doped diamond films with different doping level in gas phase are deposited on Co-cemented tungsten carbide (WC-Co) inserts using hot filament chemical vapor deposition (HFCVD) method. Trimethyl borate ((CH3O)3B), tetraethoxysilane (Si(OC2H5)4) and urea (CO(NH2)2) are dissolved in acetone to serve as boron, silicon and nitrogen precursors, respectively. The as-deposited diamond films are characterized by field emission scanning electron microscope (FESEM), Raman spectroscopy and indentation tests. The results suggested that doping source and doping level will affect the surface morphology, growth rate, quality and adhesion of diamond film. The optimized doping level to obtain diamond films deposited on WC-Co substrate for mechanical applications with well faceted crystal, low defect, low cluster structure and high adhesive strength is 5000 ppm, 10000 ppm and 10000 ppm for boron, silicon and nitrogen doping, respectively.