c-BN coating produced by arc-jet plasma

c-BN coating with the thickness of 1 mm was produced on an Mo substrate. Arc-jet deposition was performed in a mixture of Ar and N/sub 2/ gases. h-BN was used as the precursor. The equipment included a W-hollow cathode with plasma density about 10/sup 14/ cm/sup -3/ at 200 A discharge current. The Ar pressure in the working chamber was 1 Torr and the residual pressure was of 10/sup -2/ Torr. The working substrate temperature ranged from 500 to 1000/spl deg/C and the film growth rate was about 0.2 mm/h. Chemical analysis reveals the presence of carbon. The electron diffraction pattern (JEM-100C) corresponds to polycrystalline cubic structure with a crystalline mean size of 1000 /spl Aring/ and lattice constant a=3.58 /spl Aring/.