Simultaneous enhancement of anti-friction and wear resistance performances via porous substrate and FeCoNiTiAl high entropy alloy coating of artificial joint materials

It remains an extreme challenge to fabricate artificial joint materials with applicability of mechanical properties compared with bones, superior biocompatibility, anti-friction and wear resistance performances. Here, we report an effective strategy to simultaneously enhance the anti-friction and wear resistance performance of Ti6Al4V substrate through optimizing the porosity and sputtering a high-entropy alloy (HEA) coating. The progressive scratch experiments are carried out to equivalently imitate the scratch deformation pro-cess induced by hard particles and evaluate the anti-friction and wear resistance perfor-mances, which directly reveal the significantly decreased coefficient of friction (COF) of porous substrate based on suitable pore diameter covered with HEA coating compared with pure Ti6Al4V substrate. The porous design is verified to effectively weaken the stress shielding effect and simultaneously improve the hydrodynamic lubrication. Attributed to the coupling effects of pore structure-induced "flexibility" and HEA coating-induced sur -face hardening, the composite structure exhibits low COF value, wear volume and enhanced scratch resistance. The design concept would facilitate the development of novel medical implant materials with requirements of anti-friction and wear resistance. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).