Catalytic Growth of High-Performance Graphite-like Carbon Films on a Nitrided Substrate: Experimental Study and First-Principles Calculations

This study reports a novel process for the fabrication of high-performance graphite-like carbon (GLC) films on nitrided substrates through successive steps in a plasma nitriding system. Unlike films fabricated via conventional dual treatments (nitriding + film deposition), here-fabricated GLC films were grown on the surface of nitrided steel via a catalytic reaction. A transition zone having a nanocrystalline and amorphous structure was observed at the interface between the nitrided substrate and GLC films, which increased the durability of GLC films because this structure enhanced the adhesion of GLC films on the nitrided substrate, improving resistance to spallation and wear. Experimental study and first-principles calculations showed that the Fe3N phase had a stronger catalytic effect on GLC films than the Fe4N phase, and GLC films grown on the nitrided layer dominated by Fe3N were thicker with stronger adhesion and excellent frictional and wear properties compared with GLC films grown on the nitrided layer dominated by Fe4N because of the beneficial structure formed at the interface. This study reports a simple and inexpensive method to fabricate a dual layer containing high-performance GLC films via a catalytic growth and interface matching mechanism.