A permanent magnet if kept and used in optimum working conditions will keep its magnetism for years. It’s estimated that neodymium magnets only lose approximately 5% of their magnetism every 100 years.
Optimum working conditions include not subjecting a magnet to temperatures above its maximum operating temperatures, protecting the magnet from corrosion, and finally not subjecting them to strong demagnetising fields.
How long will a neodymium magnet last?
Neodymium magnets are permanent magnets and lose a fraction of their performance every 100 years if maintained within their optimum working conditions.
There are two factors that can shorten a magnet’s lifespan.
Heat
If the temperature of a magnet exceeds the maximum operating temperature, then the magnet will lose magnetism that will not be recovered on cooling. The maximum operating temperature of N42 Neodymium magnets is 80°C.
Samarium Cobalt magnets are not quite as strong as Neodymium magnets but they do have a much higher operating temperature of up to 350°C.
Corrosion
If the plating on a magnet is damaged and water can get inside, the magnet will rust and again this will result in a deterioration in magnetic performance.
Samarium Cobalt magnets and Ferrite magnets are both resistant to corrosion but aren’t as strong as Neodymium magnets.
