Comparative study of the tribological behaviour of superhard nanocomposite coatings nc-TiN/a-Si3N4 with TiN

Superhard nanocomposite nc-TiN/a-Si3N4 coatings were prepared by reactive magnetron sputtering (RMS) and pulsed dc plasma-induced chemical vapour deposition (PCVD) on stainless steel substrates. The tribological behaviour of these coatings at room and elevated temperature was compared with that of TiN coatings deposited by RMS and PCVD. The results show that the superhard nanocomposite nc-TiN/a-Si3N4 coatings have a somewhat higher friction coefficient of 0.55-0.7 at room temperature that decreases to about 0.4-0.5 at 550 °C. However, the friction coefficient of pure TiN coatings is 0.6 at room temperature and increases to 0.7 after a sliding distance of 0.1 km at 550 °C.