Bonded Rare earth magnets pose another problem. The magnetic powder is separated with non-magnetic binder which affects the penetration of flux through the magnet during the pulse and requires a higher magnetic field than one would expect from the rule above. For example, MQP-B powder with an Hci of 10,000 Oersteds requires at least 30,000 Oersteds to saturate. Most magnet manufacturers should be able to provide you with a curve of peak applied field versus percent of saturation for induction, Hci or percent of maximum flux output.
Approximate required magnetizing fields for various magnet types to reach at least 98% of maximum output are listed below. These are general and affected by fixturing and LC circuit, etc.
The general rule is that to saturate a magnet, one must apply a peak field of between 2 and 2.5 times the intrinsic coercivity. For example, an Hci of 20,000 oersteds will require at least 40,000 oersteds to saturate.
In reality, it’s the sorting equipment that may cause problems. Steel rollers, walls, etc. can pose a problem if the magnetic field extends outside your package with too much strength. This is true whether you are shipping via air or ground.
Make sure the magnets have ample space around the magnet to that there isn’t much attraction force outside the box. A magnet’s attractive strength drops very quickly with distance, so this usually isn’t too hard. View the Force vs. Distance curves under the “Technical” tab on any of our product pages for more details. For example, a DX0X0 1″ diameter x 1″ tall cylinder has a Force to a steel plate vs. Distance curve like this.
We don’t recommend shipping Neodymium magnets in a plain envelope. Even small ones can reach through the thin paper walls. If it sticks to your refrigerator door, it’s probably not a good idea to mail it.
he recommended maximum working temperatures are indicators of likely performance but the user should review their design for suitability or contact us for design assistance. The letter nomenclature is as follows (where xx is the Maximum Energy Product in MGOe):-
Nxx 12000 Oe / 955kA/m (minimum)80 deg C / 175 deg F suggested maximum
NxxM 14000 Oe / 1115kA/m (minimum) 100 deg C / 212 deg F suggested maximum
NxxH 17000 Oe / 1355kA/m (minimum) 120 deg C / 248 deg F suggested maximum
NxxSH 20000 Oe / 1590kA/m (minimum) 150 deg C / 302 deg F suggested maximum
NxxUH 25000 Oe / 1990kA/m (minimum) 180 deg C / 356 deg F suggested maximum
NxxEH 30000 Oe / 2385kA/m (minimum) 200 deg C / 392 deg F suggested maximum
NxxVH / NxxAH 35000 Oe / 2785kA/m (minimum) 230 deg C / 446 deg F suggested maximum