Manufacturer and Supplier of Strong Permanent Magnets
Manufacturer and Supplier of Strong Permanent Magnets
Manufacturer and Supplier of Strong Permanent Magnets
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    A magnet is an object that has a magnetic field. The word magnet comes from the Greek "magnitis lithos", which means "Magnesian stone." Magnesia is an area in Greece where deposits of magnetite have been discovered since antiquity.In the modern sense, a magnet is any material that has a magnetic field. It can be in the form of a permanent (or static) magnet or an electromagnet. Permanent magnets do not rely upon outside influences to generate their field. Electromagnets re...

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    Modern permanent magnets are made from special alloys to create increasingly better magnets. The most common families of magnet materials today are: Ferrites; Alnicos (Aluminum-Nickel-Cobalt); Ceramics; Samarium-Cobalts; and Neodymiums (Neodymium-Iron-Boron, NdFeB). Neodymiums and Samarium-Cobalts are collectively known as Rare Earths.

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    The grade, or "N rating" of the magnet refers to the Maximum Energy Product of the material that the magnet is made from. It refers to the maximum strength that the material can be magnetized to. The grade of neodymium magnets is generally measured in units millions of Gauss Oersted (MGOe). A magnet of grade N48 has a Maximum Energy Product of 48 MGOe. Generally speaking, the higher the grade, the stronger the magnet.

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    If a magnet is stored away from power lines, other magnets, high temperatures, and other factors that adversely affect the magnet, it will retain its magnetism essentially forever.

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    The factors can affect a magnet's strength: heat; strong electrical currents in close proximity to the magnet; Neodymium magnets will corrode in high humidity environments unless they have a protective coating. Shock and vibration do not affect modern magnet materials, unless sufficiently strong to physically damage the material itself.

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    The strength of a magnetic field drops off roughly exponentially over distance.

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    Provided that the material has not been damaged by extreme heat, the magnet can be re-magnetized back to its original strength.

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    Once a magnet is fully magnetized, it cannot be made any stronger - it is "saturated". In that sense, magnets are like buckets of water: once they are full, they can't get any "fuller".

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    Most commonly, Gaussmeters, Magnetometers, or Pull-Testers are used to measure the strength of a magnet. Gaussmeters measure the strength in Gauss, Magnetometers measure in Gauss or arbitrary units (so its easy to compare one magnet to another), and Pull-Testers can measure pull in pounds, kilograms, or other force units. Special Gaussmeters can cost several thousands of dollars. 

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    No. The Br value is measured under closed circuit conditions. A closed circuit magnet is not of much use. In practice, you will measure a field that is less than 13,900 Gauss close to the surface of the magnet. The actual measurement will depend on whether the magnet has any steel attached to it, how far away from the surface you make the measurement, and the size of the magnet (assuming that the measurement is being made at room temperature). For example, a 1" diameter N-48 Neo magnet t...