Investigation of the effects of different nitride coatings on tribological and surface properties of CoCrMo and CP-Ti alloys used in biomedical applications

Biomaterials are synthetic materials used in implant treatment to restore the function of natural living tissues and organs in the human body and to improve human health. CP-Ti and CoCrMo alloys are frequently used biomaterials in implant treatment. Surface coating process is applied in order to eliminate the deficiencies of biomaterials and to provide desired new properties. In this study, TiN and ZrN materials were coated on CP-Ti and CoCrMo alloy samples by Cathodic arc PVD method. The structural characterization of coated and uncoated surfaces was performed by XRD, SEM and EDS methods; the wettability behaviour of the surfaces was evaluated by contact angle measurements and the mechanical strengths were evaluated by microhardness tests, and comparative analysis was performed. In order to examine the effect of the coating process on tribological performance, wear tests applied to uncoated and coated samples. The obtained data revealed that the coating application provided a significant increase in surface roughness and microhardness values. In addition, it was analysed that TiN and ZrN coatings made on Ti samples decreased the hydrophilicity of the surface as a result of the surface coating. It has been analysed that TiN coating on CoCrMo samples makes the surface more hydrophilic, while ZrN coating reduces hydrophilicity.