Graded surface structure of bioactive Ti-15Mo-5Zr-3Al alloy

摘要

A bioactive graded surface structure of an amorphous sodium titanate which was free of alloying species of Mo, Zr and Al was formed on Ti-15Mo-5Zr-3Al alloy by NaOH and heat treatments. The sodium titanate transformed into a hydrated titania via Na~+ ion exchange with H_3O~+ ion to induce bonelike apatite formation on the alloy substrate in a simulated body fluid (SBF). The alloying species neither released into SBF nor affected the apatite formation. Thus-formed apatite was integrated with the alloy substrate by graded structure where the apatite on top surface gradually changed into alloy substrate through hydrated titania and titanium oxide. This graded structure provides a strong interfacial bonding strength between the apatite layer and the alloy substrate.