Bioactive NiTi shape memory alloy fabricated by oxidizing in H2O2 solution and subsequent NaOH treatment

A bioactive NiTi shape memory alloy (SMA) with wormlike surface structure was fabricated using a composite treatment by oxidizing in H2O 2 solution and subsequent NaOH treatment. The characteristic parts of XRD patterns of the surface of NiTi SMA after having oxidized in a boiling 30% H2O2 solution and subsequently treated in 1 M NaOH solution in comparison with the chemically-polished NiTi substrate was shown. The XPS, SEM, and XRD reveal that a Ti oxide layer was firstly formed on the surface of NiTi substrate after having oxidized in H2O2. The improvement of the bioactivity of NiTi SMA results from the modified surface by the formation of sodium titanate/TiO2 surface layer.