Tribological study of TiN monolayer and TiN/CrN (multilayer and superlattice) on Co-Cr alloy

The wear performance of the Co-Cr alloys used for total joint replacement is a critical variable for the success of the implant. In order to add information in this field, the effect of superlattice coatings on wear response was investigated. In this work, TiN/CrN superlattices produced alternating TiN and CrN layers of nanometer-scale, were deposited by the means of reactive magnetron sputtering technique using two types of disc substrates: cast Co-Cr (ASTM F75) and cast Co-Cr+1 wt% B alloys. As the first attempt, a simple ball-on-disc tribological configuration was performed using Ringer׳s solution and Al2O3 balls. In addition, scratch testing, optical and scanning electron microscopy were used to elucidate on the wear mechanisms involved. Adhesive and abrasive wear mechanisms were found on the wear track. Co-Cr+1 wt% B showed massive secondary phases precipitation which increases the adherence resistance in the interface between the system coating and the substrate improving slightly the wear response.