December 19, 2017
With an aging population, demand is stronger than ever for pacemakers and defibrillators. With increased usage of Magnetic Resonance Imaging (MRI), it is important that permanent implants are made from non-magnetic materials, such as UNS R 30035.
UNS R 30035 Nickel alloys keeping pace
UNS R 30035, a cobalt-nickel-chrome-molybdenum superalloy, with 33-37% nickel content, has been used successfully in pacemaker lead wires, conducting signals from the pacing module to the heart. Medical device designers require highly reliable materials because pacemakers are permanent implants, remaining in the body for years.
In the last several years, 35N LT® a proprietary version of UNS R 30035 (commonly known as MP35N®), has been developed by US-based Fort Wayne Metals specifically for demanding medical applications. The alloy is double melted, initially using Vacuum Induction Melting (VIM), followed by Vacuum Arc Remelting (VAR). This enables consistent controlled chemistries and exceptionally low inclusions levels, the cause of fatigue failure if it should occur.
“We have seen demand for 35N LT® grow considerably in the medical industry”, says David Snyder, process engineer at Fort Wayne Metals. “It is increasingly used for pacing leads due to its excellent corrosion resistance, fatigue resistance and biocompatibility. It is also very cost-competitive in comparison to alternatives, such as platinum and tellurium.”
Supporting higher voltage defibrillators
While pacemakers use batteries, which release the needed energy slowly, defibrillators require capacitors so high voltage electrical energy can be released quickly. The lead wires for defibrillators are therefore composite wires or drawn filled tubing (DFT) wire manufactured by Fort Wayne Metals. DFT wires consist of narrow tubes made from 35N LT® with a silver wire inside the tube.
35N LT® is also used for stylets, catheters and orthopaedic cables, among other applications. The excellent features of this material will continue to inspire medical device designers into new possibilities and innovations.