Electrochemical reaction mechanism of milled surface of NiTi shape memory alloy.

• Electron transfer velocity on milled surface were explained by plastic deformation. • Reversibility of electrochemical reaction was studied by cyclic voltammetry. • Electrochemical reaction products on milled surface of NiTi alloy were investigated. NiTi shape memory alloy is widely used in medical field because of its excellent properties. Milling machining has become one of the main processing methods in the medical field due to its good shape adaptability. However, the change of the shape and properties of milled surface affects its biocompatibility and corrosion resistance. Electrochemical machining is used as the follow-up process of milling machining. The polarization curve method, cyclic voltammetry method and constant potential electrolysis are used in this paper to study the electrochemical reaction mechanism of the NiTi alloy milled surface. The results show that the plastic deformation layer appears compared with the original material, making electrode reactions and electron transfer relatively difficult. The surface eventually forms TiO 2 , without the formation of Ni-related oxide. The electrochemical reaction mechanism of the NiTi alloy milled surface in the HClO 4 -CH 3 COOH system provide important theoretical guidance for the production and manufacturing of medical products. [ABSTRACT FROM AUTHOR]