Inhibiting fretting corrosion of titanium

A process for treating a titanium containing artefact to inhibit fretting corrosion is specified, in which an active species having a higher heat of formation of its oxide than titanium is deposited on the artefact in vacuo, and the artefact is then heated sufficiently to cause the active species to migrate into the artefact to provide a surface region thereof containing the active species. Preferably the active species is deposited by an ion bombardment technique. The preferred active species are barium, strontium, rubidium, europium, caesium, ytterbium and calcium. (author)