Nickel titanium is a highly durable, strong metal with a number of medical and other applications. Its key properties are shape memory and high elasticity, which can make it useful for settings where other metals might break down. This metal can be complicated to manufacture, and requires special facilities to control its quality and purity. The sophisticated fabrication process used can make nickel titanium products more costly than those made with other metals.
This is an example of an alloy, a mixture of two or more metals that combines their unique characteristics to develop a product with specific desired traits. In the case of nickel titanium, when the metals are combined under controlled conditions, they develop very high elasticity. The metal can bend and flex readily without cracking or breaking, maintaining this trait in both cold and hot conditions. This can be extremely useful for things like medical devices, which may need to withstand considerable strain without failing.
In addition to being very elastic, this metal has an excellent shape memory. This means that after bending, it will return to its previous shape and can hold that shape through numerous flexing sessions. This allows manufacturers to create products that will maintain their integrity over time, even under stress. For devices like surgical stents used to open blood vessels, these two traits are essential. Bending prevents damage to the blood vessel, while shape memory keeps the stent open even after it's compressed.
Producers of nickel titanium need to work it in a vacuum and tightly control temperature to bring out the desired metal characteristics. Once the alloy is ready, it can be formed into products like surgical implants and medical tools. It can also be used for the production of metal components used in a wide variety of other settings where people need a strong, lightweight, flexible metal that can retain its shape under adverse conditions. Producers can make plates, coiled wire, and other base materials for smaller companies as well as individuals to work with in the production of custom components.
The widespread use of nickel titanium in the medical community has been a cause for concern among some advocates. Nickel is a known allergen and some research suggests it may also be carcinogenic, which makes it less than ideal for introduction into the human body. Biocompatibility researchers who look at materials to determine if they can safely be used in a medical setting believe nickel titanium is generally safe, although there may be some special circumstances in which it is not appropriate.