A novel antibacterial and biocompatible Ta-Ag coating fabricated by cold spray technology

Infection caused by the bacterial contamination is a critical problem challenging the application of medical implant in orthopaedic and dental surgeons. Consequently, medical implants having antibacterial ability are highly demanded. Tantalum and silver were respectively characterized by excellent biocompatibility and antibacterial ability, but due to their significantly different properties it is challengeable to manufacture Ta-Ag component via thermal processing method. Herein, by taking the advantage of unique characteristics of cold spray technology, it is the first time that antibacterial and biocompatible Ta-Ag coating was successfully fabricated. In the CS process, two types of powders, mechanical mixed Ta-Ag and immiscible Ta-Ag alloy powders were used to fabricated CSed Ta-Ag coating and their deposition behaviour was systematically investigated. It was found that a better deposition efficiency was obtained by mechanically mixed Ta-Ag powder, but Ag could aggregate in the coating and Ta were prone to rebound, which induced heterogenous distribution of Ag and mass loss of Ta. On the contrary, coating fabricated by immiscible Ta-Ag alloy has homogenous Ta and Ag distribution, but higher cold spray parameters were required to obtain better deposition efficiency.