Can magnets that have lost their magnetism be re-magnetized?
That depends on how the magnetism was lost. Usually magnets can regain their original strength unless they’ve been exposed to extreme heat.
Can magnets be made stronger?
Once a magnet is fully magnetized, it cannot be made any stronger.
How long do magnets hold their magnetic strength?
If the magnets are not subjected to external magnetic fields high enough to cause demagnetization - and/or - elevated temperatures above the advertised maximum use temperature the field will remain at or near as received. This could be expected last for the life of the application.
What materials can be used for magnetic shielding?
In general, magnetic field attenuation is a function of the permeability of the material. A better shielding material has high permeability per weight. For metallic foil and sheet, the most efficient shielding material is the 80 Nickel family (e.g., Molypermalloy), followed by the 50 Nickel alloys (e.g., Deltamax). The economical silicon-steel foils and sheets are also good shielding material when weight is not of a major issue.
Are there any regulations for shipping magnetized materials?
According to the United States Department of Transportation and the Office of Hazardous
Materials Safety, it is against regulations to ship a magnet by air that maintains a field of more than 0.00525 gauss measured at 4.5 meters (15 feet) from any surface of the package. This is to prevent the magnet from interfering with the operation of the aircraft's navigational compass. There are no federal regulations that restrict the shipping of magnetized materials by ground transportation. Please check with your commercial carrier for additional specifics.
Magnetization
Neodymium magnets require extremely high magnetizing fields and particular consideration must be given to this when designing complex assemblies. Neodymium can be magnetized in any direction as long as it is aligned properly. In some instances multiple pole magnetization is not possible; when it is possible, special fixtures are required.
Temperature constraints
The temperature coefficient of neodymium has triggered several grades to be developed to meet specific operating requirements. Please refer to our chart of magnetic properties to compare the characteristics of each grade. Before choosing a neodymium magnet be sure to consider your application’s maximum operating temperature.
What can Neodymium magnets do?
Magnets affect electrically charged particles and electrical conductors. Magnets have the ability transform electrical energy without losing their own energy. These effects can perform useful functions, for example:
Electrical-to-mechanical effects are key in the function of motors, loudspeakers, and equipment that requires charged particle deflection.
Mechanical-to-electrical effects are useful in generators, motors and microphones
Mechanical-to-heat effects facilitate eddy current and hysteresis torque devices.
Mechanical-to-mechanical affects, Magnetic separators, Sensors.
Other effects of magnets include magneto-resistance and magnetic resonance.
General information on Neodymium Iron Boron Magnet Materials
Sintered neodymium-iron-boron (Nd-Fe-B) magnets are the most powerful commercialized permanent magnets available today, with maximum energy product ranging from 26 MGOe to 52 MGOe. Nd-Fe-B is the third generation of permanent magnet developed in the 1980s. It has a combination of very high remanence and coercivity, and comes with a wide range of grades, sizes and shapes. With its excellent magnetic characteristics, abundant raw material and relatively low prices, Nd-Fe-B offers more flexibility in designing of new or replace the traditional magnet materials such as ceramic, Alnico and Sm-Co to achieve high efficiency, low cost and more compact devices.
A powder metallurgy process is used in producing sintered NdFeB magnets. Although sintered NdFeB is mechanically stronger than Sm-Co magnets and less brittle than other magnets, it should not be used as structural component. Selection of Nd-Fe-B is limited by temperature due to its irreversible loss and moderately high reversible temperature coefficient of Br and Hci. The maximum application temperature is 200 °C for high coercivity grades. Nd-Fe-B magnets are more prone to oxidation than any other magnet alloys. If Nd-Fe-B magnet is to be exposed to humidity, chemically aggressive media such as acids, alkaline solutions salts and harmful gases, coating is recommended. It is not recommended in a hydrogen atmosphere.
Neodymium magnets are a member of the Rare Earth magnet family and are the most powerful permanent magnets in the world. They are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B).
What information should I provide when ordering?
We will help you with your order. Usually we ask for the following information.
Material type and grade required.
Size and shape, if available, a sketch or drawing with dimensions and tolerances.
Max working temperature.
Delivered magnetized or unmagnetized? Magnetization direction?
Quantities required.
Coating required (if any)
Information on what you want to use the magnet for.