How strong are magnets?
The answer to how strong magnets are is simple:
- Neodymium magnets are very strong
- Ferrite magnets are less strong
But it is not quite that simple, because in addition to different magnet types, the size and density also have a lot to say about how strong a magnet is.
The bigger and thicker a magnet is, the stronger it is - but you can't just keep doubling the strength: as soon as you reach the same dimensions for width and height (e.g. 10x10 or 20x20 mm.), the doubling of the strength stops. The same applies when you attach several magnets with the same density. It is easiest to explain with a concrete example, where we start with magnets with N45 values:
- 10x10 mm. the magnet has a strength of 3.9 kg.
- 10x20 mm. has a strength of 4.4 kg.
In other words: maximum strength is reached when the height exceeds the diameter / width of the magnet.
The two different types of magnets can accomplish distinct tasks. Ferrite magnets can better withstand heating, whereas neodymium magnets are better for freezing environments. A very small magnet is needed to achieve a very high strength when choosing the neodymium type magnets (power magnets).
Do they need to be very strong magnets?
Neodymium is needed to create strong permanent magnets (which does not need to be electrified) that can carry their own weight a thousand times. A 2x1 mm. magnet weighs less than 0.01 grams and is capable of carrying 130 grams. The bigger the neodymium magnet gets, the bigger weight it can carry.
The density plays a big role in the magnet, the higher the N-value of the magnet, the stronger it is. You can have two magnets that are the same size, but if one has a higher N-value than the other, you can easily achieve a strength difference of a few kilograms on a 20-mm-diameter magnet.
Doesn't the strength matter that much?
It depends on the size and strength of the magnets, it's easy to make very strong ferrite magnets, but these will be large and heavy. It's important to clarify whether you need a small and strong magnet or whether the price is the overriding factor. Ferrite magnets aren't bad magnets, they're just not super strong.
We will explain it with a comparison below:
Comparison of magnets
We like to compare a 10x10mm ferrite magnet to a 10x10mm neodymium magnet.
Neodymium is the clear winner with 3.9 kg. against ferrite's 0.4 kg. That's a big difference in strength for two magnets of the same size. But they serve different purposes and you can save a lot by buying ferrite magnets instead.