Maximum Operating Temperature VS. Curie Temperature
Introduction
Magnets are materials that generate a magnetic field and have the ability to attract or repel other magnets or ferromagnetic materials. They are commonly used in a wide range of applications, such as in electric motors, generators, speakers, and magnetic sensors. However, magnets can lose their magnetic properties at high temperatures, which is an important consideration when selecting a magnet for a specific application.
Here, this article is going to talk about the maximum operating temperatures and Curie temperatures of different magnets. Hope that you can have a further comprehension of how temperature affects the properties of magnets and select the perfect magnets for your projects.
Figure 1. Magnets
Maximum Operating Temperature VS. Curie temperature
Let’s start from the comparison between the maximum operating temperature and Curie temperature, two important temperature-related properties of magnets. These two terms are often used confusingly, but they have distinct meanings and implications for magnet performance.
— Maximum Operating Temperature
The maximum operating temperature of a magnet is the highest temperature at which it can maintain its magnetic properties, such as its magnetic field strength and magnetic orientation.
This temperature is determined by the magnetic material’s composition and manufacturing process, and it can vary widely depending on the specific magnet.
–The Curie Temperature
On the other hand, the Curie temperature of a magnet is the temperature at which it loses its ferromagnetic properties and becomes paramagnetic. This occurs because the thermal energy is sufficient to overcome the magnetic ordering of the electrons in the material, causing them to become randomly oriented. Above the Curie temperature, the magnet no longer exhibits a net magnetic field and cannot attract or repel other magnets or ferromagnetic materials.
The Curie temperature is also dependent on the magnetic material’s composition and can vary widely depending on the specific magnet. It is a fundamental property of the material, and cannot be changed by altering the manufacturing process or the magnet’s shape or size.
Operating Temperatures of Different Permanent Magnets
Here are the operating temperatures and Curie temperatures of some of the most commonly used permanent magnets. Yet, it’s important to note that the actual operating temperature of a permanent magnet will depend on a variety of factors, including its size, shape, and the strength of the magnetic field it is exposed.
NdFeB magnets are the strongest type of permanent magnets available and are commonly used in motors, generators, and other industrial applications. These magnets have a maximum operating temperature of approximately 150°C and a Curie temperature of about 310-400°C.
SmCo magnets are known for their excellent temperature stability and are commonly used in aerospace and defense applications. These magnets can withstand operating temperatures of up to 310°C, and their Curie temperature is 700-800°C.
Alnico magnets are made from a combination of aluminum, nickel, and cobalt and have been used in various applications for over 50 years. These magnets can operate at temperatures up to 525°C. Also, do not exceed the Curie temperature of 800°C.
Ferrite magnets, also known as ceramic magnets, are commonly used in consumer electronics and other low-cost applications. These magnets have a maximum operating temperature of 250°C and a Curie temperature of around 450°C.
Table 1 Maximum Operating Temperatures and Curie Temperatures
| Maximum Operating Temperature/℃ | Curie Temperature/℃ | |
| Nd-Fe-B Magnet | M (80-100), H (100-120), SH (120-150), UH (150-180), EH (180-200). | 310-400 |
| Sm-Co Magnet | 310-400 | 700-800 |
| Al-Ni-Co Magnet | 525 | 800 |
| Ferrite Magnet | 250 | 450 |
Conclusion
In summary, the maximum operating temperature of a magnet refers to the highest temperature at which it can maintain its magnetic properties, while the Curie temperature is the temperature at which it loses its ferromagnetic properties and becomes paramagnetic. These two temperatures are important considerations when selecting a magnet for a specific application, and it is important to ensure that the magnet’s maximum operating temperature is below the operating temperature of the application to avoid loss of magnetic properties.
Stanford Magnets has rich experience in the manufacturing and sale of permanent magnets of different sizes and shapes. Customization is also welcome. Send us an inquiry if you are interested.
Related reading: List of Magnets That Can Withstand High Temperatures