title: Joint replacement components made of hot-forged and surface-treated Ti-6Al-7Nb alloy.
abstract: We have developed a titanium-aluminium alloy with the inert alloying element niobium. The optimal composition was found to be Ti-6Al-7Nb (Protasul-100). This custom-made alloy designed for implants shows the same alpha/beta structure as Ti-6Al-4V and exhibits equally good mechanical properties. The corrosion resistance of Ti-6Al-7Nb in sodium chloride solution is equivalent to that of pure titanium and Ti-6Al-4V. This is due to a very dense and stable passive layer. Highly stressed anchorage stems of different hip prosthesis designs have been made from hot-forged Ti-6Al-7Nb. The polished surfaces of hip, knee and wrist joints made of Ti-6Al-7Nb and articulating against polyethylene are surface-treated by means of a very hard and 3-5 microns thick titanium nitride coating (Tribosul-TiN) or by oxygen diffusion hardening (Tribosul-ODH) to a depth of 30 microns.
authors.affiliation: Sulzer Medical Technology Ltd., R&D Biomaterials, Winterthur, Switzerland.
authors.forename: M F
authors.initials: MF
authors.lastname: Semlitsch
authors.forename: H
authors.initials: H
authors.lastname: Weber
authors.forename: R M
authors.initials: RM
authors.lastname: Streicher
authors.forename: R
authors.initials: R
authors.lastname: Schön
mesh_terms: D006801:Humans; D007595:Joint Prosthesis; D014025:Titanium / Q000737:chemistry*
chemical_list: C070282:Ti-6Al-7Nb alloy; D014025:Titanium