Improvement of mechanical properties and cutting performance of modified MT-TiCxN1 − x coating by moderate temperature chemical vapor deposition

To improve the cutting performance, a modified MT-TiCxN1 − x coating (x = 0.63) that adheres well to carbide substrates was developed by introducing C2H4 gas to a TiCl4-CH3CN-H2 precursor system on a TiN base layer during moderate temperature low pressure CVD. Glow-discharge optical emission spectroscopy and X-ray diffraction analyses reveal an increase in the incorporated carbon content. Electron backscatter diffraction analysis shows a highly preferred orientation [(422) plane] with a very fine columnar grain size of 0.17 ± 0.06 μm. The increase in hardness and the decrease in friction coefficient for cutting AISI: 51200 and AISI: 316 at room temperature and 600 °C with the modified MT-TiCxN1 − x coating result in a 30% longer tool life for continuous cutting of carbon steel (AISI: 1055) and alloyed steel (AISI: 4137) and a 60% longer tool life for stainless steel (AISI: 316). The modified MT-TiCxN1 − x coating resistance to failure was determined by four-groove intermittent cutting of AISI: 4137, and it shows a 30% increase in the average number of impacts compared with a conventional MT-TiCxN1 − x coating.