CHEMICAL VAPOR DEPOSITION OF TUNGSTEN CARBIDE LAYER FOR CUTTING TOOL

摘要

Chemical vapor deposition process to deposit tungsten carbide layer for cutting tool was investigated using WF_6 as a W source and CH3CN or CH_4 as a C source. Cemented carbide and TiN coated cemented carbide were used for substrates. The single-phase WC layer was deposited by WF_6-CH_3CN-H_2-Ar system at 950℃, whereas the composite phase of WC and the other tungsten carbides was deposited by both the WF_6-CH_4-H=8 system at 1040℃ and WF_6-CH+10_3CN-H2-Ar system at 850 and 900℃. Micro-structural investigation by scanning electron microscopy revealed that the microstructure of the deposited layer was influenced by the substrate as well as the deposition condition. Cutting test was performed to evaluate the effect of tungsten carbide layer as an intermediate layer between the substrate and TiCN layer.