Influence of sputtering atmosphere on the structural, biological, and electrochemical properties of tantalum-containing coatings on the NiTi alloy

Abstract

The magnetron sputtering method was used to deposit tantalum-containing coatings on NiTi shape memory alloys under Ar, ArO2, and ArN2 atmospheres. The main focus of this research is on how the deposition atmosphere can significantly impact not only the morphological and microstructural properties of coatings but also their corrosion behavior and in vitro biocompatibility. In this research, FESEM observations, GI-XRD crystallinity measurements, AFM topographical investigations, electrochemical measurements, and MTT assay were employed to determine to what extent the deposition atmosphere affects the morphology, microstructure, roughness, corrosion behavior, and in vitro biocompatibility properties, respectively. FESEM studies reveal that tantalum sputtered under the Ar atmosphere has a more uniform, and compact structure, while round-like particles appear on the surface under ArO2 and ArN2 atmospheres. The GI-XRD patterns indicate that the substrate temperature of 300°C is not sufficient for the formation of crystallized structure. It has been shown that the sample deposited under the ArN2 atmosphere has more negative charges; this is associated with higher protein adsorption on its surface and increases endothelial proliferation rates. Moreover, the presence of Ta2O5 on the surface of the ArO2 atmosphere leads to the highest corrosion resistance.