Features of the surface layers of TiNi-based alloy thin ribbons

The chemical composition of the surface of TiNi-based alloys in the form of ribbons produced by rapid melt quenching in oxygen-containing environment has been investigated. It is shown that titanium oxide is formed on the Ti₅₀Ni₂₅Cu₂₅ alloy surface, while on the Ti_39.2Ni_24.8Cu₂₅Hf₁₁ alloy surface titanium and hafnium oxides are formed. Atomic-force microscope images reveal crystalline structures of titanium oxide with sizes of up to 500 × 500 nm² on the surface of the Ti₅₀Ni₂₅Cu₂₅ sample. After removing the surface oxide layer by ion etching, the ratio of elements becomes close to the stoichiometric composition.