What is Nitinol?

Interested in using Nitinol in your medical device design? Read to find answers to questions like: What is Nitinol? Where did Nitinol come from? How does Nitinol work? Are there different types of Nitinol? Where can I buy Nitinol? In this blog post, you’ll learn all the basics of Nitinol, its history, composition, and applications.  

Meet Buehler and Wang  
In 1959, William J. Buehler and Frederick E. Wang were conducting research at the Naval Ordinance Laboratory in Maryland when they discovered the unique properties of this alloy. While Buehler was working on developing a missile nose cone that could better withstand fatigue, heat, and impact, he found that a 1:1 alloy of nickel and titanium showed promise. When he presented a sample at a laboratory meeting, heat from a pipe lighter was applied, showing its versatile characteristics. And so, Nitinol became a household staple in the medical device world.  

FUN FACT: The name “Nitinol” comes from its composition, Nickel and Titanium, and its place of discovery, the Naval Ordinance Laboratory in Maryland.  

How Does Nitinol Work?  
The properties of Nitinol rely on its dynamic crystalline structure. The molecular structure is sensitive to external stress and temperature. The alloy has three defined temperature phases:  

1. Austenite Phase (Hot Phase)– temperature is above the activation temperature. The transition temperature varies depending on the exact composition of the Nitinol alloy. Nitinol comes in many activation temperatures from 30°C (86°F) to 130°C (266°F). 

2. Martensitic Phase (Cold Phase) – the low temperature phase. The crystal structure is needle-like and is collected in small domains. Within the small domains, the needle-like crystals are aligned. The alloy may be bent or formed easily. Bending transforms the crystalline structure of the alloy, producing an internal stress.  

3. Annealing Phase (Setting Phase)– high temperature phase. The alloy will reorient its (cubic) crystalline structure to remember its present shape. The annealing phase for Nitinol is 500°C.  

Are There Two Different Types of Nitinol?  
Yes! Nitinol offers two unique properties: shape memory and super elasticity. Here is the breakdown of the two.  

1. Superelasticity: This is a phenomenon when Nitinol gets back to its previous shape, and it is difficult to deform. In this state, it almost acts like spring steel.  

2. Shape Memory: This can be easily deformed at the activation temperature. In this state, it acts closely to how tin wire acts, but with one difference, it can’t bend to any too acute angles. 

Explanation of Nitinol For Beginners 

1. Superelastic Nitinol acts like a super spring. When it’s in a warm state (usually in the austenite phase), you can stretch or bend it, but it quickly snaps back to its original shape as soon as you let go. It’s very hard to permanently bend it in this state. It’s like trying to bend a strong spring or spring steel.  

2. Shape Memory happens when Nitinol is in its cooler, bendable state (the martensitic phase). In this state, you can bend and shape it more easily, kind of like tin wire, but with one big difference: you can’t bend it into very sharp angles. Once you heat it back up, it remembers its original shape and goes back to it on its own. 

Where Can I Buy Nitinol Mandrels or Wire?  
Component Supply offers a comprehensive stock of superelastic Nitinol  with diameters ranging from 0.003” to 0.055”.  
Although it comes in many finishes, we stock the most common one, light oxide. This type is diamond drawn with an amber or dark brown surface color. This wire is frequently chosen for applications that demand superelasticity at both room and body temperatures.  
 
Common uses include guidewires, stents, stylets, forming mandrels, stone retrieval baskets, and orthodontic files. 

Buy standard 36″ and 72″ lengths through: 

🌐 Website: https://www.componentsupplycompany.com/nitinol-wire/ 
📧 Email: parts@componentsupplycompany.com 
📞 Phone: 931-761-4000 

Looking for anything custom? Think shape set, radiused ends, or custom cut lengths. You can request a rapid quote directly through www.cscustomfab.com/quote or call us!