Plasma CVD of hard coatings Ti(CNO) using metallo-organic compound Ti(OC3H7)4

The use of the metallo-organic compound Ti(OC3H7)4 with auxiliary heating plasma CVD (MOPCVD) of hard coatings Ti(CNO) is reported. The harmful effect of chlorine on the film properties and on the PCVD equipment could be avoided in this way. The deposition rate decreased from 2.4 to 1.2 μm/h when the oven temperature ranged from 120 to 420°C, and the maximum microhardness value of the Ti(CNO) coatings can reach 16 000 MPa. The coatings were analyzed with SEM and XRD. The coatings showed the typical columnar structure. The XRD analysis revealed that the d(200)-values of the Ti(CNO) films decreased from 0.2130 to 0.2123 nm with increasing the oven temperature. The chemical composition of the films was measured by XPS. The films were mainly composed of titanium, carbon, nitrogen and oxygen. The bonding energies of Ti2p3/2 and Ti2p1/2 of the Ti(CNO) films were 458.70 and 463.75 eV, respectively. The cutting tests have shown that the average lifetime of φ65 mm HSS drills coated with the MOPCVD-Ti(CNO) was 7.3 times as long as that of uncoated ones; the average lifetime of φ65×5 mm HSS milling cutter coated increased by a factor of 8.