Microstructure and hardness of Ti(C, N) coatings on steel prepared by the activated reactive evaporation technique

Abstract In view of the potential demand for wear-resistant coatings deposited at low substrate temperatures for applications in the cutting tool industry, titanium carbonitride films were prepared by the activated reactive evaporation technique on high speed steel substrates. Titanium was evaporated in C 2 H 2 N 2 plasmas of various compositions ranging from pure C 2 H 2 to pure N 2 , i.e. in C 2 H 2 with 0, 30, 50, 70 and 100 vol.% N 2 . Knoop hardness values (at 50 gf load) were obtained both on top and in the cross section of each deposit and ranged from 2200 to about 5900, reflecting the variations in chemical composition and microstructure of the films. X-ray diffraction, transmission electron microscopy and scanning transmission electron microscopy analyses were performed to reveal those microstructural features of importance to the coating properties, i.e. phase composition, grain morphology and defect distribution (in particular, void and crack formations).