Nitinol Devices & Components

Laser cutting and wire forming are 2 of the most commonly used processes in the manufacture of Nitinol medical devices.This study explores how varying the amount of material removed during the final surface treatment steps affects the corrosion resistance of Z-type stents that have either been laser-cut from tube or shape set from wire.All parts were subjected to a typical heat treatment process necessary to achieve an Austenite finish (A_f) temperature of 25 ± 5 °C, and were subsequently post-processed with an electrochem. passivation process.The total weight loss during post-processing was recorded and the process adjusted to create groups with less than 5%, less than 10%, and less than 25% amounts of weight loss.The parts were then crimped to 6 mm and allowed to expand back to their original diameterThe corrosion test results showed that on average both groups of Z-stents experienced an increase in the corrosion breakdown potential and a decrease in the standard deviation with increasing amounts of material removal.In addition, less material removal is required from the wire-form Z-stents as compared to the laser-cut Z-stents to achieve high corrosion resistance.Finally, 7 day nickel ion release tests performed on the wire-formed Z-stents showed a dramatic decrease from 0.0132 mg of nickel leached per day for the low weight loss group to approx. 0.001 mg/day for the medium and high weight loss groups.

Nitinol alloys (Nitinol) exhibit a dramatically enhanced elasticity, known as "superelasticity", which is becoming integral to the design of a variety of new medical products. Elasticity is the most apparent of the advantages afforded by this material, but by no means the only or most important. Also discussed in this paper are features such as biocompatibility, kink resistance, constancy of stress, physiological compatibility, shape memory deployment, dynamic interference and fatigue resistance. Each of these properties is discussed and highlighted through example. Examples presented include stents, filters, retrieval baskets, and surgical tools.

A review on the microscopic mechanisms and macroscopic effects of SMEs.