Abstract
Titanium metal and its alloys coated with a hydroxyapatite by plasma spray method are widely used as hip joints and dental implants. Thus formed apatite is, however, not easy to be controlled in its composition and structure, and not easy to be strongly bonded to the substrates. In the present study, it was attempted to induce bioactivity of titanium metal by forming a thin titanium hydrogel layer on its surface with a chemical treatment. The pure titanium metal was treated with 10M-NaOH or -KOH aqueous solution at 60°C for 24h to form alkali titanate amorphous layer on its surface, then subjected to a heat treatment at 600°C for 1h to increase the thickness of the amorphous layer up to 1μm thick. Thus treated titanium metal formed a dense and uniform bone-like apatite layer on its surface via forming a titanium hydrogel layer when it was soaked in a simulated body fluid with ion concentrations nearly equal to those of human blood plasma.
