Shenzhen Wuge Industrial Co., Ltd

Nickel titanium alloys generally do not have magnetism or only have weak magnetism. The following provides a detailed explanation of its composition, structure, and applications:

1、 Basic composition and structure of nickel titanium alloy

Composition: It is mainly composed of nickel (Ni) and titanium (Ti), with a common atomic ratio close to 1:1 (such as NiTi alloy), and sometimes other elements (such as copper, niobium, etc.) are added to adjust its properties.   

Crystal structure: A "phase transition" occurs at different temperatures, such as from a high-temperature phase (austenite, with a regular structure) to a low-temperature phase (martensite, with a more complex structure). This phase transition is the key to its shape memory effect and superelasticity, but it does not produce strong magnetism during the phase transition process.   

Nickel titanium memory alloy wire

2、 Why are nickel titanium alloys usually non-magnetic?

The essence of magnetism: The magnetism of matter is mainly determined by unpaired electrons in atoms. Metals such as iron, cobalt, and nickel are easily magnetized due to the presence of a large number of unpaired electrons, exhibiting strong magnetism (ferromagnetism).   

Electronic structure of nickel titanium alloy:

Nickel forms metal bonds with titanium in alloys, causing changes in electron distribution and a decrease in the number of unpaired electrons, even to the point where they are almost non-existent.   

Titanium itself belongs to weak magnetic metals (paramagnetism), and the high content of titanium in the alloy further weakens the overall magnetism.   

3、 Weak magnetism under special circumstances

Processing or ingredient impact:

If the nickel content in the alloy is too high (beyond the ideal ratio), or impurities such as iron are introduced during the production process, weak magnetism may be generated.   

Cold processing (such as rolling and stretching) may cause small stresses or structural defects within the alloy, resulting in extremely weak paramagnetism (only slightly reactive in strong magnetic fields).   

Test conditions:

When using a regular magnet to approach nickel titanium alloy, it is almost not attracted; If professional equipment (such as a vibrating sample magnetometer) is used for measurement, extremely weak magnetic signals (extremely low magnetization) may be detected.   

4、 The advantage of "non-magnetic" in application scenarios

Medical field: used for making vascular stents, orthodontic wires, etc. Non magnetic can avoid interference with magnetic resonance imaging (MRI) equipment and ensure examination safety.   

Precision instruments: such as sensors, optical components, etc., non-magnetic can prevent the impact on equipment accuracy.   

Aerospace: When used in a strong magnetic field environment, it will not fail due to magnetism, meeting the requirements of special working conditions.   

5、 Magnetic comparison with other alloys

The "non-magnetic" nature of nickel titanium alloys is determined by their composition and crystal structure, which gives them unique advantages in fields such as healthcare and precision manufacturing. If a certain nickel titanium alloy product is found to have obvious magnetism, it may be caused by compositional deviation or the introduction of impurities, which needs to be confirmed through professional testing.