Microstructure and bioactivity of a cold sprayed rough/porous Ta coating on Ti6Al4V substrate

To improve the bioactivity and biocompatibility of titanium implants, a rough/porous tantalum (Ta) coating was firstly prepared on Ti6Al4V substrate by cold spraying. The results indicated that the surface of Ta coating is extremely rough with lots of visible holes, because of poor deposition quality. Microstructure and microhardness results showed that different layers appeared in the inner and outer parts of coatings, corresponding to porosity, due to lack of subsequent compaction. The simulated body fluid (SBF) soaking test showed that spherical apatite sediments were mineralized on rough/porous surface in SBF after 2–4 weeks, which demonstrated that the cold sprayed Ta coating had good bioactivity. This was mainly attributed to the rough/porous surface of Ta coating obtained by cold spraying, which is conducive to the heterogeneous nucleation of apatite on it.