Special properties of nickel-titanium alloy
Nitinol is a binary alloy composed of nickel and titanium. In addition to its unique shape memory function, it also has a series of excellent properties, making it an excellent functional material.
1. Shape memory property. When a nickel-titanium alloy is deformed by external force at a certain temperature, it can still maintain the deformed shape after the external force is removed, but it can automatically return to its original shape at a higher temperature.
2. Superelasticity[i]. The superelasticity of nickel-titanium alloy can change with the change of heat treatment conditions. When nickel-titanium alloy wire is heated to above 400℃, the superelasticity begins to decrease.
3. Corrosion resistance. Studies have shown that the corrosion resistance of nickel-titanium alloy is better than the best medical stainless steel currently available, so it is widely used in the medical field.
4. Biocompatibility. Although nickel is carcinogenic, the titanium dioxide on the surface of nickel-titanium alloy acts as a barrier, which can inhibit the release of nickel, making nickel-titanium alloy have good biocompatibility.
5. Good shock absorption. The initial vibration amplitude of superelastic nickel-titanium alloy wire is only half that of stainless steel wire.
Applications of Nickel-Titanium Alloys
Nickel-Titanium alloys' excellent properties have led to their widespread use in aerospace, automotive, and medical devices.
1. Aerospace
Nitinol alloy applications in aerospace primarily include aircraft pipe fittings, spacecraft antennas, fasteners, connectors, electrical connections, and electromechanical actuators.
2. Automotive
Nitinol alloys are commonly used in automotive engine heat shield fan clutches, exhaust gas automatic regulating nozzles, diesel engine radiator vent automatic switches, and shape memory springs in jet engine oil filters.
3. Medical Devices
Nitinol alloys have been successfully used in orthodontics, orthodontic and plastic surgery, and minimally invasive cardiovascular interventions. Other products currently in clinical trials include surgical sutures, cerebral aneurysm clips, contraceptive rings, and micropumps for artificial hearts and kidneys.
4. Civilian Products
Civilian products primarily include superelastic eyeglass frames, mobile phone antennas, bra supports, high-elasticity and high-tenacity fishing line, and headphone covers.
