Novel layered tribological coatings using a superelastic NiTi interlayer

This paper presents a study on using the superelastic NiTi alloy as an interlayer between CrN coating and aluminum substrate to improve the interface adhesion and wear resistance. Nanoindentation, scratch adhesion, and pin-on-disk wear measurements were conducted to study the adhesion and tribological behaviors of the layered coatings. We found that the superelastic interlayer could significantly improve the adhesion between the hard coating and metallic substrate. Furthermore, coatings with the superelastic interlayer had lower friction coefficient and better wear resistance than coatings with traditional metallic adhesion-improvement layers (e.g., Cr). We attribute the improved adhesion and wear performance to the high hardness to Young's modulus ratio of the layered coating structure with the superelastic interlayer.