Wear behavior of pits textured grey cast iron rings with Zr/ZrN coatings under dry sliding

This study presents the influence of Zr/ZrN coatings on the tribological performance of pits textured grey cast iron parts under dry sliding. A laser marking system and a physical vapor deposition equipment were applied to manufacture pits textured grey cast iron rings combined with Zr/ZrN coatings. A pin-on-disc wear test rig was used to reveal the wear behavior of samples under dry wear condition, at a rotating speed of 200 r/min, with a normal load of 70 N. The wear losses and the worn surfaces of all rings were obtained by an electronic balance and a three-dimensional surface profilometer, respectively. The results show that Zr/ZrN coatings can significantly increase the surface roughness and surface hardness of grey cast iron rings. As a result, Zr/ZrN coatings increase the friction coefficients of all coated GCI rings, and reduce the wear losses of some ones. In this work, when surface texturing combines with Zr/ZrN coatings, the final tribological properties of coated grey cast iron rings may be either improved or deteriorated, depending on surface characteristics, texturing parameters and loads. Compared with the uncoated smooth grey cast iron ring, Zr/ZrN coatings cannot effectively improve the wear behavior of pits textured samples. Among all coated grey cast iron rings, when the diameter of the pit is 0.8 mm, and the distance between pits is 1.25 mm, the pits textured grey cast iron ring can provide the optimal anti-wear performance. This work would provide a valuable reference for the surface design of journal bearings and roller bearings.