Nanomechanical and morphological characterization of titanium carbide coatings for osseointegration

Titanium implants are widely used for osseointegration application due to their biomimetic properties and low specific weight. However, they show a low wear resistance in the harsh conditions of biological environment, which could be the cause of tissue inflammation and production of fibrotic tissues. To avoid such problems, an efficient protection for titanium components is mandatory. Titanium carbide coatings can provide an excellent protection for the titanium implants because of their mechanical and morphological properties. In this work we report the mechanical and morphological characterization of titanium carbide coatings on titanium substrate deposited by Ion Plating Plasma Assisted (IPPA) deposition. Nanoindentation showed that TiC coatings have higher hardness and elastic modulus than the most commonly used coatings (hydroxyapatite, titanium nitride, titanium oxide). Focused Ion beam and AFM characterization showed that the coating appears to be strongly bonded with the substrate and that it replicates very well the titanium surface. Morphological characterization also showed that the surface of TiC coatings consists of agglomerates of spherulitic nanostructures, which improve the adhesion of the osteoblast cells and promote their growth. Finally, in vitro tests confirmed an improvement in the production of mRNA's of proteins involved in the ossification process.