Introduction
The strength of various magnets is affected by shape, size, and most importantly ambient temperature. Therefore, it is very important to know the effect of temperature on magnetic force before choosing a magnet. In this article, this effect will be explained using some examples of high-temperature resistant magnets.
How Does Temperature Affect Magnets?
Let’s start by looking at some basic information about how temperature affects magnets.
- Cold instead of hot: In general, heat reduces magnetism, and cold increases magnetism. Magnets prefer cold environments, so they may work when used at room temperature.
- Maximum operating temperature vs. Curie temperature: When a magnet is heated to its maximum operating temperature, it irreversibly loses some of its magnetic force. All magnetization is lost when the ambient temperature exceeds the Curie temperature. The maximum operating temperature and Curie temperature depend on the type and quality of the magnet.
- Reversible Loss VS. Irreversible Loss: To compensate for reversible loss, bring the magnet back to room temperature. Nevertheless, magnets with irreversible loss cannot recover the lost magnetization.
High-Temperature Magnets
Now let’s look at some strong magnets that can withstand high temperatures. See the table below for the corresponding maximum operating temperature and Curie temperature.
1. Al-Ni-Co Magnets – 525°C
Al-Ni-Co magnets are made of aluminum, nickel, cobalt, and iron and have a maximum operating temperature of 525°C. It is, therefore, suitable for very hot work areas. Moreover, alnico magnets appeared on the market quite early. They were available commercially in the 1960s and replaced by rare earth magnets in the 1980s. Nonetheless, these powerful magnets are still commonly used to make sensors, guitar pickups, and other high-temperature devices.
Related article: What Is an Alnico Magnet & What Is Alnico Magnet Used for?
2. Ferrite Magnets – 250°C
Ferrite magnets, or ceramic magnets, contain large amounts of iron oxide and small amounts of other metallic elements. Ferrite magnets have a relatively low maximum operating temperature of 250°C but are widely used due to their low cost. They are also called ceramic magnets because of their very high electrical resistance. These desirable properties make ferrite magnets used in various applications such as transformers, computer cables, etc.
3. Sm-Co Magnets – 310 ~ 400°C
Sm-Co magnet has a strong magnetic force, and its maximum operating temperature is 310 ~ 400°C. Sm-Co magnets are less powerful than neodymium magnets, but have a higher temperature rating, making them suitable for high-temperature or cryogenic applications. In addition, these magnets have excellent properties such as excellent oxidation resistance, corrosion resistance, and extreme demagnetization resistance. Stanford Magnets mainly offers two types of Sm-Co magnets (1:5 series and 2:17 series).
4. Nd-Fe-B Magnets – 80~200℃
Nd-Fe-B magnet or Neodymium magnet is one of the most common magnets, and its working temperature can reach 200 degrees Celsius. Neodymium magnets are also available in various grades, and their maximum temperature can be divided into M (80-100°C), H (100-120°C), SH (120-150°C), UH (150-180°C), and EH (180-200°C).
Conclusion
Al-Ni-Co magnets, ferrite magnets, Sm-Co magnets, and neodymium magnets are high-temperature resistant strong magnets. However, check the maximum operating temperature and Curie temperature of each in advance. Stanford Magnets is a leading supplier of high-temperature permanent magnets. Visit our homepage to get quality magnets for your home or business.
