Ti6Al4V coatings on titanium samples by sputtering techniques: Microstructural and mechanical characterization

Abstract

Although titanium is widely used as biomaterial, the control of the interface properties between its surface and the surrounding physiological environment (like bone, other tissues or biofluids) results crucial to achieve a successful osseointegration and good biomechanical and functional performance. In this work, commercially pure titanium (Grade IV) discs obtained by conventional powder metallurgy were coated with 1–3 µm of Ti6Al4V (Grade V) alloy using DC-pulsed or high-power impulse magnetron sputtering (HiPIMS) technique with the aim of improving their biomedical performance. SEM, confocal microscopy, X-ray diffraction, nanoindentation and wetting measurements are used to evaluate the bio-interface role of the titanium-coated implants. Conformal Ti6Al4V coatings with controlled nano-roughness can be deposited with enhanced mechanical (H = 5–8 GPa; E = 140–160 GPa) and hydrophobic properties thanks to a dense columnar structure. The increased Ti-O bonding at the interface helps to prevent the corrosion due to the formation of a surface passivation layer. Particularly in the case of the HiPIMS process, the surface modification of titanium implants (chemistry, morphology and structure) appears as an effective strategy for satisfying the biomedical requirements and functionality, with enhanced mechanical properties and nanostructuration for prevention of bacteria colonization.