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Today I was sorting through some of my modelling stuff and found some small neodymium magnets still in the clear plastic bag they came in, only they had half corroded away to metallic dust. Considering these were only bought a couple of years ago I thought I would do some research on the matter. I found out Iron neodymium magnets can corrode easily just in the atmosphere if they haven't been given a protective coating. On the flipside the gold ones I bought around the same time are perfectly fine. I guess that's the price for buying cheap.

Has anyone else notcied this? Has anyone had magnetised models falling apart after a few years? Or is it odd that I have got this far into my modelling "career" without knowing this can happen?

Anything iron/steel-based could corrode.

Sure but there is clearly a much faster rate of corrosion than your average car rusting in the rain when the magnets turn to dust inside a sealed clear plastic bag in a couple of years.

Your car is also painted, it's not raw metal, raw metal is going to corrode considerably faster than treated metal.

I have magnetized models pressing 7-8 years old. No corroding to dust.

Maybe if we went middleschool science fair and stored them in water or something, but I have never heard of such a thing.

 Brokksamson wrote:
Your car is also painted, it's not raw metal, raw metal is going to corrode considerably faster than treated metal.

Clearly. The point is I put no thought to the idea i could be buying magnets which weren't treated properly.To my eyes they could have been zinc coated or whatever (how would you know). Now it's something to think about when I am buying magnets.

There is also a correlation between magnetic fields and corrosion. Just like there is between electrical interactions and rust.
Mine are nickel plated (to be more accurate, zinc and nickel plated - the nickel adheres better to the zinc coating than to the raw steel. It's a metallurgy thing.) and are still shiny and fine - but nickel plate really doesn't like being exposed to humidity, heat and/or salt air for too long, either (the plating flakes off).