Author:

Keywords:

Coronary stents, Electrochemical polishing, Surface roughness of stents, 11 Medical and Health Sciences, Biochemistry & Molecular Biology

Abstract:

Surface roughness is one of the properties that determines the performance of coronary stents. Therefore, in the production and application of stents, surface polishing is of paramount importance. In the present study, electrochemical polishing was performed on 316L stainless steel slotted tube coronary stents made by laser cutting. Additionally, both acid pickling and annealing, as the pretreatment of electrochemical polishing, were also conducted. Material removal of the stents (both weight loss and strut width change) in the process of both pickling and electrochemical polishing was investigated. Both qualitative and quantitative roughness measurements were made to evaluate stent surface quality. Furthermore, material characterization of the stents was determined by means of composition analysis, metallographic characterization, and hardness measurement. The removal of material during both pickling and electrochemical polishing was within an acceptable range. Pickling caused a decrease in roughness of the cutting zone. Annealing resulted in an increase in roughness of the stent surfaces. Electrochemical polishing caused a smooth stent surface, which is comparable to commercially available stents. Moreover, the annealing treatment caused the stents to change from a deformed microstructure to a homogeneous structure, which is the major determining factor for the expandability of balloon stents.