How permanent is a magnet’s strength?
What might affect a magnet’s strength?
Heat
Radiation
Strong electrical currents in close proximity to the magnet
Other magnets in close proximity to the magnet
Neo magnets will corrode in high humidity environments unless they have a protective coating.
Will magnets lose their power over time?
Which are the strongest magnets?
The most powerful magnets available today are the rare- earth types. Of the rare-earths, neodymium magnets are the strongest. However, at elevated temperatures (of approximately 150°C and above), samarium cobalt magnets can be stronger than neo magnets, depending on the magnetic circuit.
What are superconductors?
Can I make a magnet that I already have stronger?
Can a magnet that has lost its magnetism be re-magnetized?
Provided that the material has not been damaged by extreme heat, most magnets can be re-magnetized back to their original strength.
How do you measure the strength or power of a magnet?
If I have a neo magnet with a Br of 12,300 Gauss, will I be able to measure 12,300 Gauss on its surface?
No. The Br value is measured under closed-circuit conditions. A closed-circuit magnet is not of much use. In practice, you will measure a field that is less than 12,300 Gauss close to the surface of the magnet. The actual measurement will depend on whether the magnet has any steel attached to it, how far away from the surface you make the measurement, and the size of the magnet (assuming that the measurement is being made at room temperature). For example, a 1" diameter Grade 35 neodymium magnet that is ¼" long will measure approximately 2,500 Gauss when 1/16" away from the surface, and 2,200 Gauss when 1/8" away from the surface.