Why magnets dont rust ?

[Young Frankenstein]

Dont they have metal in them ?

 

[Boomer]

Magnets do rust. Those that don't are often coated with something like a plastic.

 

[Young Frankenstein]

I would have to debate this one since I havent seen any plastic cover on any of my powerheads.

 

[renogaw]

difference in magnet makes? i know i've gotten the epoxy covered magnets from gaussboys and they rusted fast.

 

[MMM33732]

Theres a few different types of magnets and all have different properties. Ceramic or Ferrite Magnets do not corrode or rust easily. Alnico Magnets are an aluminum and nickel mixed in the alloy with the iron, and are not prone to rusting or corroding. With Samarium Cobalt Magnets, rust and corrosion from water is not a big factor. Not sure about salt water though. Neodymium-Iron-Boron Magnets rust very easily and are usually coated in a protective coating of some sort.