The Art of Mastering Metals
Specialty metals have been a vital part of the medical industry, specifically in the development of medical devices. From basic diagnostic guide wires to sophisticated body implants, these metals keep growing their list of medical uses through the years.
Stainless steel has been the champion of the medical device market through the last decades. It is obviously the alloy of choice for most design engineers, who know all of its benefits, including corrosion resistance, variety of forms and finishes, and low cost.
Titanium is another popular and highly versatile metal used to make medical devices. Like stainless steel, it is corrosion-resistant and causes less negative reactions when connected to human bone, compared to other metals. The process that allows natural bone and tissue to fully attach to a titanium implant is known as osseointegration. It is a staple in the medical manufacturing business as it is used to make a huge variety of products, from neurostimulation instruments to orthopedic rods, pins and plates, and of course, heart implants.
In recent years, there has been a growing interest in niobium and its alloys in the medical device manufacturing community. The metal’s inertness makes it a common choice for making pacemakers and other devices similar. When treated with sodium hydroxide, niobium creates a porous layer that promotes osseointegration, making it a good alternative for internal medical applications.
Tantalum has been used in the medical device industry for over four decades, particularly as a catheter plastic compounding additive and in the manufacture of diagnostic marker bands. It is also widely preferred for making implants and other shaped-wire applications because it is corrosion-resistant and highly ductile. It also has excellent dielectric properties and is easy to weld.
Nitinol is an alloy made of nickel and titanium (around 51% Ni) and can be superelastic when under applied stress. Shape memory gives the metal the ability to return to its original shape when heated over its transformation temperature. This extraordinary property of nitinol, on top of its being chemically and physiologically compatible with the human body, makes it a favorite among medical device engineers and designers.
Finally, the medical industry seems to have shifted its views on copper and is even focusing research funding into the metal and its alloys. Copper used to be off limits for most medical uses because of its thrombogenic (bleeding) risks, but it has developed a new following in the device community. Behind this change is the fact that, when properly shielded, the metal can effectively carry signals to small implants and diagnostic tools. Companies behind the manufacture and processing of copper for medical devices usually make the shielded metal wire or strips with their own dedicated equipment for the purpose of maintaining superior quality and preventing cross contamination.