A scanning electrochemical microscopy characterization of the localized corrosion reactions occurring on nitinol in saline solution after anodic polarization

SENSORS AND ACTUATORS B-CHEMICAL

卷:321

Article

Asserghine, Abdelilah¹  Medvidovic-Kosanovic, Martina³  Stankovic, Anamarija³  Nagy, Livia^1,2  Souto, Ricardo M.⁴  Nagy, Geza^1,2 

[1] Univ Pecs, Fac Sci, Dept Gen & Phys Chem, Ifjusag U 6, H-7624 Pecs, Hungary

[2] Univ Pecs, JanosSzentagothai Res Ctr, Ifjusag U 20, H-7624 Pecs, Hungary

[3] Univ Osijek, Dept Chem, Cara Hadrijana 8A, HR-31000 Osijek, Croatia

[4] Univ La Laguna, Inst Mat Sci & Nanotechnol, POB 456, E-38200 Tenerife, Canary Islands, Spain

关键词: Antimony microelectrode;    Hydrogen evolution;    Localized corrosion;    Nitinol;    Passivity breakdown;    Scanning electrochemical microscopy;   

DOI  :  10.1016/j.snb.2020.128610

来源: Elsevier

【 摘 要 】

Scanning electrochemical microscopy (SECM) in a combined amperometric/potentiometric operation was used to characterize the electrochemical activity of nitinol, before and after anodic treatment, in 0.1 M NaCl solution. The SECM operation in the feedback mode showed that the nitinol surface was homogeneously passive after surface finishing and storage under ambient conditions, while heterogeneous surface characteristics occurred after application of anodic polarization, even for a limited time. That is, the development of anodic and cathodic sites has been detected due to the onset of localized corrosion processes on the metal surface. The evolution of hydrogen gas from localized sites was monitored using SECM in the substrate generation/tip collection mode (SG/TC), while SECM operated in potentiometric mode was used to map the pH distribution in the electrolyte volume adjacent to the nitinol surface. Local acidification was observed around anodic spots associated with the Ni2+ discharge, as well as alkalinization above the cathodic zones.

【 授权许可】

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