Interfacial structure control of cubic boron nitride films prepared by ion-beam assisted deposition

Boron nitride films were prepared by ion beam assisted deposition (IBAD). The films were synthesized by depositing boron vapor under simultaneous bombardment with nitrogen ions and nitrogen-argon mixture ions. Cubic boron nitride (c-BN) films with enhanced tribological properties had been explored by inserting a B-rich layer as a controlled buffer at the interface. Tribological characterizations of the buffer layer and the double-layered BN films consisting of the c-BN layer underneath with the B-rich buffer layer have been performed. Successful growth of c-BN layer has been observed on the B-rich layer and the hardness of the films increased almost linearly with increasing fraction of the sp(3) bonded cubic phase in the c-BN layer, The control of the interfacial structure exhibited a significant effect on the improvement of the tribological properties of the films due to the effective relaxation of internal stress of the c-BN films.