Laser deposited AISI 316L reinforced with fine grained titanium carbonitride: Tribocorrosion performance compared to CoCrMo and friction behaviour against articular cartilage

Hemiarthroplasty, a medical procedure consisting of replacing half of the affected joint, was introduced during the last decades as a less aggressive alternative to full replacement surgery. However, it has been widely observed that the remaining native cartilage left after hemiarthroplasty, total knee arthroplasty without patella resurfacing and other partial resurfacing procedures which create a metal-on-cartilage interface, experiences accelerated wear when in contact against metallic implants. This study evaluates the potential of additive manufactured AISI 316L containing fine grained titanium carbonitride reinforcements as an alternative to the widely spread CoCrMo alloy. To this end. The tribocorrosion performance of laser deposited reinforced 316L is investigated in buffered solution against alumina. The coefficient of friction of 316L reinforced with titanium carbonitride has a similar value than CoCrMo, even though friction is more stable. The tribocorrosion wear is a factor 3 lower under open circuit conditions and almost an order of magnitude at applied passive potential. During tribocorrosion, 316L reinforced with titanium carbonitride has a lower release of metal ions (Fe and Ni) when compared to Co release in CoCrMo, as anticipated by the lower current density measured during sliding. Additional in vitro experiments are performed against osteochondral plugs collected under aseptic conditions from a bovine medial femoral condyle. The in vitro experiments reveal a low and stable coefficient of friction of reinforced 316L against cartilage throughout the experiment with a value of 0.039 ± 0.009, comparable to literature values reported for CoCrMo. Since 316L reinforced with titanium carbonitride is not cytotoxic, these results highlight its potential for use in biomedical applications where resistance against tribocorrosion wear is required.