Microstructure and mechanical properties of Ti-Si-C-N films synthesized by plasma-enhanced chemical vapor deposition

A systematic investigation of the microstructure and mechanical properties of Ti-Si-C-N films was conducted as a function of Si contents. The Quaternary Ti-Si-C-N films were synthesized on AISI 304 stainless steel and Si wafer by Radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) using a gaseous mixture of TiCl4, SiH4, CH4, Ar, N2, and H2. The substrate temperature during film growth was maintained constant at 600 °C. The Si addition into Ti-C(0.6)-N(0.4) film resulted in microstructure and mechanical modification, i.e., a crystal phase of Ti(C,N) diminished and an amorphous phase of Si3N4/SiC appeared. The quaternary Ti-Si(9.2 at.%)-C-N film had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by the amorphous phase of Si3N4/SiC. The microhardness of the film increased from ∼ 24 GPa for Ti-C-N film and reached to a maximum hardness of ∼ 46 GPa for Ti-Si(9.2at.%)-C-N film. In addition, the average friction coefficient of the Ti-Si-C-N films largely decreased with increasing Si content.