Films with different compositions within the B-C-N system have been grown by Ion Beam Assisted Deposition (IBAD) using two e-beam sources to evaporate simultaneously boron and carbon under concurrent N2+ assistance. This technique allows full control of the B, C, and N fluxes impinging to the substrate surface, so that a wide range of different BCN coating compositions can be obtained. Using this system, we have deposited coatings with the BCxN composition (x between 0.25 and 4) showing a hexagonal-like structure. These coatings show hardness values around 20 GPa, regardless the C content in the films. Higher hardness values (30 GPa) have been obtained for B4CNx films (i.e., B4C with increasing amounts of N).
The wear rates of BCxN coatings with 1 m thickness decrease with the C content, from 10-6 mm3/cycle for 20 % C (i.e. close to TiN films) to 10-8 mm3/cycle for 80 % C ( ta-C films), with not delamination after 100.000 cycle in the wear tests. The friction coefficient in the BCxN coatings varied between 0.18 and 0.35, which is close to the values found in ta-C.