Characterization of fretting fatigue damage of PVD TiN coated biomedical titanium alloys

Fretting fatigue is a form of adhesive wear damage due to small oscillatory movement between two contacting bodies under the action of uniform or non-uniform cyclic loads. Cyclic loads may be experienced due to vibration of one or both the bodies eventually leading to failure at the contact area. Fretting damage is also experienced by load bearing implants within the body environment such as hip joints, knee joints, bone plates, etc. Damage characterization is important from the view of minimizing in-vivo failures. Titanium alloys are frequently used as bioimplants due to its excellent biocompatibility and low modulus of elasticity compared to stainless steel or Co–Cr–Mo alloys. Fretting wear damage of load bearing implants can be minimized through suitable surface modification process. Ti–6Al–4V and Ti–6Al–7Nb are commonly used for biomedical applications and PVD TiN coated alloys are used for our fretting fatigue studies. Fretting fatigue life of PVD TiN coated alloys improved compared to uncoated alloys.