Topographical hard protective coating for joint replacement implants

Joint replacement surgery, essential for managing joint diseases, requires improvements in tribocorrosion performance to ensure surgical success and longevity of joint implants. Transition-metal light-element (TMLE) compound coatings, known for their high hardness and chemical stability, have been extensively researched and applied for surface protection of joint implants. However, these coatings typically lack a lubrication phase, leading to high friction coefficients and severe corrosion wear, which makes long-term effective protection challenging. A promising approach is to utilize the natural lubricating proteins present in body fluids, which are continuously available and can thus address long-term service issues of TMLE coatings. In this work, we utilized micro-arc oxidation (MAO) technology to develop an underlying morphology, then conformally deposited a TiB₂ layer, resulting in a cratered dual-layer TiB₂/MAO coating. This unique cratered dual-layer structure not only preserves the high hardness and wear resistance of TiB₂ but also aims to (1) absorb wear particles to prevent abrasive wear and (2) increase surface energy to optimize protein lubrication capacity. Consequently, the TiB₂/MAO coating exhibits low friction coefficients and wear rates in protein-containing simulated body fluids. Furthermore, the dual-layer TiB₂/MAO coating demonstrates excellent corrosion resistance and biocompatibility. This dual-layer coating design synergistically combines the superior intrinsic properties of material with unique structural construction, while also harnessing continuously available external proteins as lubricants to further optimize performance, thereby introducing an advanced strategy for developing protective coatings for implant materials.