Study on hybrid nano-diamond films formed by plasma chemical vapor deposition (CVD)

Diamond-like carbon (DLC) films made by plasma chemical vapor deposition (CVD) have many useful properties for tribological characteristics. Especially, friction coefficient is very low. However, the films have weak points i.e., very low heatproof temperature of less than 300 °C and low hardness insufficient for industrial applications like machine tools. On the other hand, it is well known that diamond films made by plasma CVD have excellent hardness. But, they also have inferior properties for industrial applications, such as higher surface roughness and lower critical load than DLC films. In this study, we developed hybrid nano-diamond (HND) films that are formed by alternately depositing DLC films and diamond films in a same chamber. The HND films have sufficiently high hardness as well as excellent tribological characteristics due to the multi-layer structure of DLC and diamond. The process of forming HND films are discussed.