Tribological performance of hierarchical USRP texturing assisted oxide layer for biomedical pure titanium

The low surface hardness and poor wear resistant properties of commercially pure titanium implants may lead to wear-related difficulties during joint service and debris-induced implant failure. To enhance tribological performance, a hierarchical micro/nanotextured surface was fabricated on pure titanium using a combined method of ultrasonic surface rolling processing (USRP) and anodization. USRP creates hardened layers and wave-texture microtextures on substrate surfaces. The TiO 2 nanotube film on the microtextured substrate produced by subsequent anodization has about 44.6% crystallinity, which is higher than that by single anodization treatment. Tribological assessment performed using reciprocal sliding tests under dry conditions and simulated body fluid (SBF) conditions. Under dry friction test, the wear rate of treated surface dropped about 43% as compare to untreated specimen. The wear rate and coefficient of friction further decreased by 45.3% and 38.6%, respectively, after the same surface was treated with SBF. While helping to increase the hardness of the surface, this hierarchical texture can hold liquids and allow load distributions to reduce contact stresses in the component. Consequently, it favors the formation of a stable lubricating film. Overall, this work provides a practical way to maximize wear resistance and lubrication for medical titanium implant surfaces.