This is a tough question, since the determining factor is the intended role of the magnet. Ferrite magnets, although weaker, are surely cheaper, while neodymium magnets are stronger and therefore more expensive.
Yes they are. We always provide our customers with half and half polarities to guarantee that, no matter the final usage, the magnets can be made to stick together or against a metal surface without issues!
Neodymium magnets rust easily, therefore it is very risky to use them in humid environments if not adequately protected.
The solution to this problem is to use plastic-encased magnets or resin-coated pot magnets.
Among our coatings you can choose between zinc, nickel, gold, and black epoxy.
If the magnet has to come in contact with the skin, you would want to opt for a zinc-coated one. This guarantees that the magnet is nickel-free. Otherwise, the differences between the two coatings are just minor and cosmetic, the nickel being shinier and smoother.
Gold and black epoxy coatings offer a different color than the standard gray, but do not improve the grade of protection.
A marked magnet has a red or black dot on the relevant pole. This way the client knows the correct polarity and it becomes easier to assemble the magnets together (north against south).
It is a common misconception that ferrite magnets are cheaper than neodymium ones.
Having less adhesive force, in order to reach the same one as a neodymium magnet the ferrite magnet will have to be quite bigger, raising its cost.