Nanostructural characterization of sputter deposited Ti-Nb coatings byautomated crystallographic orientation mapping

Abstract AISI 316 L stainless steel (SS) and Cr Co alloys are commonly used for manufacturing biomedical implants due to their reasonably adequate bulk properties. Commercially pure (CP) Ti and its alloys are more biocompatible, but also significantly more expensive, than SS and Co Cr alloys; they have an additional advantage compared to SS and Co Cr alloys: their elastic modulus values are more compatible with those of the human bones (10–40 GPa). An interesting option would be to coat an implant with a Ti Nb thin film having adequate composition and thickness so that the coating would enhance the material biocompatibility. In this work, Ti Nb coatings were deposited on AISI 316L stainless steel and silicon substrates by magnetron sputtering and then were characterized by scanning and transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) coupled with automatic crystal orientation mapping (ACOM). The results show that films form a homogenous solid solution and that the growth modes are not modified by the Nb content and substrate material. Also, the texture changes together with the grain growth morphology with the increase in the niobium content. For a columnar structure characteristic of zone II of the zone structure diagram (SZD) there are strongly marked textures in {113} for the x-axis, {110} for the y-axis, and {111} for the z axis. These are suppressed when the growth type changes for the T zone with the variation in the alloying element content, and that could be due to the high mobility generated during the deposition process.