A ferrite magnet is a metal oxide with ferromagnetism. The magnetic properties of ferrite are also shown to have high permeability at high frequencies.
Unlike gold, zinc and nickel, an epoxy magnet coating acts as an excellent barrier to salt, ambient air, water or moisture. But it's slightly more expensive than the first three alternatives. Although it is easy to scratch, with a thickness of 15-30 um, it has good adhesion to steel with magnetic glue. Epoxy coatings are mainly used in the Marine, motor, sensor, automotive and consumer goods industries.
The advantage of Alnico magnets is high remanence (up to 1.35T), but it is easy to be magnetized and demagnetized. Do not contact ferromagnetic substances during use
This arc neodymium magnet is made of a top quality NdFeB magnetic alloy under the ISO 9002 quality systems. The magnet is magnetized through the thickness with north pole on the inner diameter. It is coated with Ni+Cu+Ni triple layers. 15 pieces of this arcs can form a circle with OD=3.75", ID=3.372" and height=0.8". Neodymium magnets are very powerful for their size and can hold up to hundred times their own weight. A neodymium magnet on average is about 7 times as strong as a ceramic magnet of the same size. These magnets have a wide variety of applications ranging from the home to the workshop to the classroom.
This arc neodymium magnet is made of grade N45 NdFeB rare earth magnetic material under ISO 9001 quality systems. It is magnetized through thickness with S pole on the inner diameter. Ten pieces of this arc magnets can form a perfect circle with OD=32mm, ID=20mm and height=6mm.