Novel nano-thin amorphous Ta-coating on 3D-printed porous TC4 implant: Microstructure and enhanced biological effects

Bone defects caused by tumors, trauma, or other bone diseases are common in clinical practice. Titanium alloy (TC4) and tantalum (Ta) are the primary metallic materials for bone repair. However, TC4 frequently suffers from poor osseointegration and implant loosening, while the high cost of Ta limits its widespread use for reconstructing large bone defects. To address this issue, this research employs magnetron sputtering (MSP) to deposit a nano-thin amorphous Ta-coating on the 3D-printed TC4 implant. SEM examinations of compressed samples show robust interfacial bonding without shedding, while the presence of Ta within the porous structure indicates high coverage. High-resolution TEM analysis first reveals a distinct multilayer amorphous zone consisting of surface TaOx, Ta-coating, and hybrid TaOx and TiOx, along with an impact-refinement nanocrystalline TC4 zone. Insufficient energy leads to the formation of amorphous layers. Meanwhile, interfacial bonding is strengthened through the solid solution of oxygen and interfacial densification of amorphous-crystalline bonding and impact compression. Biological evaluations demonstrate that the Ta-coating exhibits superior cell proliferation and bone ingrowth effects compared to TC4 and pure Ta implants, primarily attributed to the amorphous oxide composition on the surface. This study offers novel, cost-efficient, and excellent biological performance materials for bone defect implants.