Corrosion resistance and surface analysis of Nitinol finishing processes: a comparative study of chemical passivation, electropolishing, and DryLyte Technology

Electropolishing and chemical passivation treatments have long been the medical device industry standard for finishing Nitinol components due to their ability to create a corrosion resistant surface. Newer finishing methodologies such as the DryLyte Technology are being utilized within the medical device industry as an alternative to these methods. In this study, we compare the DryLyte Technology to electropolishing and chemical passivation by analyzing Nitinol test coupons for corrosion resistance using cyclic potentiodynamic polarization measurements and nickel ion release testing. The coupon surfaces are also analyzed using profilometer inspection, optical microscope images, and scanning electron microscope (SEM) images with Energy Dispersive X-ray (EDX) analysis. Corrosion and surface roughness results are compared using ANOVA statistical analysis to determine whether differences exist between the surface treatments. Optical microscope images and SEM outputs of the samples are also compared to characterize visual and elemental similarities and differences between the three technologies. Lastly mass removal is analyzed to demonstrate differences in material removal between the processes and characterize the variation within each process.