Influence of anodically grown TiO₂ nanotubes on shear strength and fatigue behavior of pure titanium

Author(s)

Chaves, Ricardo R. ; Fanton, Leonardo ; Figueiredo, Raul S. ; Caram, Rubens ; Cremasco, Alessandra

• Document type: Journal article
• Source: SURFACE & COATINGS TECHNOLOGY; v. 494, p. 6-pg., 2024-09-19.

Abstract

Titanium and its alloys are among the best materials for metallic biomedical implants owing to their well-established biocompatibility. The effects of surface conditions on the success of implant osseointegration have been investigated previously. Although yet to be applied in clinical practice, the anodic growth of TiO2 nanotubes on implant surfaces has been reported to enhance biocompatibility. However, such a coating increases the roughness of the surface, which can adversely affect the fatigue strength. The cyclical loading mode supported by most bone implants necessitates investigations into the effect of nanostructured coatings on the fatigue life of the implants. This study evaluates the rotating-beam fatigue strength (Fatigue stress ratio = -1, Number of cycles = 10(7) cycles) of pure titanium specimens coated with TiO2 nanotubes. TiO2 nanotubes are grown via anodization in an HF (0.1% vol.) aqueous solution by applying 20 V for 2 h, thus resulting in nanotubes with diameters and lengths of approximately 100 and 500 nm, respectively. The TiO2 coating, which is initially amorphous, is crystallized via thermal treatment at 370 degrees C for 3 h, thus resulting in an anatase allotrope, which has been reported to provide better conditions for the integration between the implant and bone. Results of adhesion tests show that the nanotube coating adheres well to the substrate surface and that its integrity is unaffected during fatigue tests. Meanwhile, results of fatigue tests show the insignificant effect of the TiO2 nanotubes on fatigue strength, which indicates that this coating can be used without compromising the implant fatigue life. (AU)

• FAPESP's process: 18/18293-8 - Titanium alloys: phase transformations and additive manufacturing applied to obtaining functionally graded materials
• Grantee: Rubens Caram Junior
• Support Opportunities: Research Projects - Thematic Grants