The Hot and Cold of Neodymium Magnets

How hot is too hot for your magnet? On the other hand, how cold is too cold? This is a complex issue, involving being aware of some advanced concepts in order to understand properly.

There are some basic parameters you can keep an eye on that will give you an indication of how much damage can be done to your magnets if subjected to very high temperatures.

What happens at High Temperatures?

To understand what happens to your magnets at very high temperatures, we first need to define a few terms. There are two temperatures that you need to be concerned with: The maximum operating temperature and the Curie temperature.

  • Maximum operating temperature – This is the highest temperature that your magnet can be subjected to without resulting in any damage. This is an operating limit. It is a general number assigned based on the material properties of the magnet.
  • Curie temperature – This is the temperature at which your magnet will lose all of its magnetic properties. If you meet or exceed this temperature, your magnet will be a normal piece of metal.

The range in between these two numbers is where damage occurs. Typically the damage is not proportional to the percentage you have climbed towards the Curie temperature. This means that just because you got halfway between the Max operating temperature and the Curie temperature, you will not lose half of the power of your magnet.

To compute the actual loss of power of your magnet is math and engineering intensive. Without going too much into detail, each magnet will have an operating curve based on its material makeup as well as its geometry.

When you combine these two factors, you can get an accurate picture of the precise max operating temperature and how much damage will be done when you exceed that temperature.

What Happens at Cold Temperatures

The amazing thing about rare earth magnets is that they get stronger the colder your temperature goes. Beyond going cold enough to make them brittle and break (one example would be dousing them in liquid nitrogen), it is nearly impossible damage them permanently by letting them get cold.

When operating at cryogenic temperatures, you may see a degradation of the performance of a neodymium magnet. Using our field strength curve, you can see that they will retain about 80% of their effectiveness at temperatures as cold at -196 C. The best part is, when they are brought back to room temperature, they will do so undamaged.

Temperature Cycling

You may be wondering if subjecting your magnet to a heating and cooling cycle will damage it. The short answer is no. If you stay below the max operating temperature, you will have no issues by heating and cooling your magnet.

BC Magnets offers a wide variety of neodymium magnets for your magnetic tool needs. Check out our selection today!

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