Mechanical and tribological properties of CrN coatings deposited by large area filtered cathodic arc

CrN coatings were deposited using a large area filtered cathodic arc deposition (LAFAD) technique from Cr targets under the atmosphere of pure N2 at a pressure of 0.02 Pa and temperature of 350 °C. The mechanical and tribological properties of the CrN coatings were characterized using nanoindentation and pin-on-disk tribometer. The mechanical and tribological properties of the TiN coatings deposited by the same technique were also included as a reference. It was found that CrN coatings possess lower hardness and elastic modulus than that of the TiN coatings. As compared with TiN coatings, when tested against Al2O3 balls, CrN coatings exhibit much lower friction coefficient (0.39) and wear rate (1.3 × 10−7 mm3/Nm), but the Al2O3 balls have much higher wear rate when tested against CrN coatings. When 302 stainless steel balls were used, both CrN and TiN coatings have similar friction coefficient, and the balls were seriously worn with a comparable wear rate when tested against the two coatings. No wear of CrN and TiN coatings could be seen. However, wear debris deposited on the coating surface with a similar deposition rate. The wear mechanisms of the CrN coatings are abrasion and adhesion wear, respectively, when tested against Al2O3 and 302 stainless steel balls.

► CrN coatings deposited by LAFAD technique possess lower hardness and elastic modulus.
► CrN coatings have super low friction coefficient (0.39) and 10 times lower wear rate (1.3 × 10−7 mm/Nm) when tested against Al2O3 balls as compared with TiN coatings.
► When tested against 302 stainless steel balls, no wear could be observed on both CrN and TiN coatings.
► The wear mechanisms of the CrN coatings are abrasion and adhesion wear, respectively, when tested against Al2O3 and 302 stainless steel balls.