Electrochemical dealloying of porous NiTi alloy: Porosity evolution, corrosion resistance, and biocompatibility behavior. (January 2023)

• Record Type: Journal Article
• Authors: Hosseini, S.A.; Karimidoost, M.; Emamian, M.; Mehrjoo, M.; Alishahi, M.
• Is Part Of: Intermetallics. Volume 152(2023)
• Publication Date: 2023-01
• Subjects: Porous NiTi alloys -- Electrochemical dealloying -- Corrosion -- EIS -- Nickel release -- Biocompatibility; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2022.107756
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: This study investigates the role and mechanism of electrochemical dealloying (ED) to decrease the nickel ion release and improve the biocompatibility of porous NiTi alloy. The potentiostatic dealloying was performed in an acidic solution, and the effect of ED duration on the surface morphology and composition of porous NiTi alloys was studied. The results indicated that the dealloying was initially started from the edges of primary pores by forming TiO2 clusters due to preferential Ni dissolution. Afterward, it progressively extended to the top surface and developed a fine porous structure. We proposed two atomistic and microstructural models to describe the evolution of the porous structure during ED treatment. The potentiodynamic polarization (PDP) and electrochemical impedance spectrometry (EIS) methods were employed to investigate the corrosion behavior of the treated specimens in a Ringer's solution. Atomic absorption spectroscopy (AAS) measurement revealed that 120 s ED treatment could decrease the concentration of released nickel ions during the PDP test from 4.2 ppm to <0.01 ppm. Additionally, the in-vitro cell culture and MTT assay showed that ED treatment could significantly improve the cell adhesion and proliferation on the surface of the NiTi alloy due to the formation of a superficial nickel-depleted layer with near superhydrophilic behavior. Highlights: Describing the mechanism of the electrochemical dealloying by an atomistic model. Describing the mechanism of porosity evolution by a microstructural model. Decreasing the nickel ion release in NiTi alloy after electrochemical dealloying. Improving cell adhesion and proliferation on the surface of NiTi by dealloying.