抄録
This study aims to develop a reproducible process for batch-fabricating a vascular stent from the heat-sensitive nitinol thin films. This device is often used for minimally invasive medical applications. A non-traditional machining process, electrolytic photoetching, receiving much attention recently for processing complex devices from difficult-to-etch thin films was chosen to micromachine stents. This is a process involving photoresist processing and electrolytic etching techniques. The electrolytic etching is done by controlling the anodic polarization characteristics of nitinol thin films so as to prevent creating a passivation layer on them. In order to investigate the electrochemical characteristics of nitinol thin films quantitatively in the electrolyte of 5% sulphuric acid in methanol, the anodic (potentiostatic) polarization measurements at a series of pre-determined constant potentials were conducted. The electrolyte temperature and electrode distance were also considered to be varied during the measurement. In order to optimize process parameters for electrolytic etching stents such as electrolyte temperature, electrode distance and current density, the analysis of the correlation between anodic polarization behavior of nitinol thin film and its active, passive and transpassive characteristics in the electrolyte was performed.
