When introduced into the body, the implant interacts with biological environment and may suffer corrosion. In addition, when this implant is submitted to friction, it may degrade by tribocorrosion due to the simultaneous action of corrosion by the body liquid and mechanical wear. Both corrosion and tribocorrosion are connected to the presence of proteins that cover the surface implant. The latter plays an ambiguous role on corrosion since dozens of contradictory papers pointed out their beneficial or detrimental effect. After its introduction into the body, the implant should form a direct interface with bone through structural and functional connection. The osseointegration and the strength of interfacial bond depend on surface properties of the implant, namely, its topographical and physico-chemical properties. In addition, since bone cells are sensitive to the species produced during the implant corrosion, when corrosion occurs, this may lead to impact osseointegration and to cause implant loosening. There is a strong connection between corrosion and osseointegration, both of which are worth discussion. That is the object of the present narrative review where we will discuss: (1) corrosion and tribocorrosion of titanium alloys used as biomaterials paying particular attention to the influence of proteins, (2) the effect of implant roughness and surface energy on osseointegration.

Black coatings are widely used in numerous applications e.g., decorative coatings, solar panels, optical instruments. The films are mostly prepared by liquid phase deposition or vapor phase deposition. In this paper we review the techniques of deposition and the properties of the most important black coatings. Optical properties are particularly presented and discussed.

In this paper, corrosion and tribocorrosion tests have been conducted on three biomaterials: Ti–6Al–4V and 316L steel that are well-known commercial biomaterials and Ti–10Zr–10Nb–5Ta, a new biomaterial elaborated in a levitation-melting furnace. Tests have been conducted in five different electrolytes: NaCl (9g/l), Ringer’s solution, phosphate buffered saline solution (PBS) with and without an addition of bovine serum albumin (BSA). Two amounts of BSA were used: 1 and 5 g/l. In NaCl solution, Ringer’s solution and PBS solution, Ti–10Zr–10Nb–5Ta presents the best corrosion resistance. Conversely, in the presence of proteins, 316L steel shows better resistance to corrosion in comparison with Ti–10Zr–10Nb–5Ta and Ti–6Al–4V. During tribocorrosion tests, the surfaces have been submitted to friction against an alumina ball at open circuit potential (OCP). Measurement of wear rate at the end of the tests indicates clearly that 316L steel shows better resistance to material removal in comparison with Ti–10Zr–10Nb–5Ta and Ti–6Al–4V.

The effect of nitrogen implantation on mechanical and tribological properties of Ti-6Al-4V and Ti-10Zr-10Nb-5Ta alloys was studied. Increasing implantation dose from 1 × 10¹⁶N⁺/cm²to 2 × 10¹⁷N⁺/cm²leads to increase gradually both hardness and Young's modulus. The results show that implantation of 2 × 10¹⁷N⁺/cm²allowed to double the value of Young's modulus and to triple the value of hardness. Friction tests that have been conducted against 100Cr6 steel and alumina balls showed that tribological behavior of the two alloys depend on the nature of the counterpart material and is strongly affected by the implanted dose of nitrogen.