Permanent magnetic materials: Permanent magnetic materials will not disappear after being magnetized by an external magnetic field, which can provide a stable magnetic field to the external space. There are four commonly used measurement indicators for NdFeB permanent magnets:

1. The units of remanence (Br) are Tesla (T) and Gauss (Gs) 1Gs = 0.0001T

A magnet is magnetized by an external magnetic field in a closed circuit environment until the technology is saturated and then the external magnetic field is cancelled. At this time, the magnetic induction intensity of the magnet is called remanence. It represents the maximum magnetic flux value that the magnet can provide. It can be seen from the demagnetization curve that it corresponds to the situation when the air gap is zero, so the magnetic induction intensity of the magnet in the actual magnetic circuit is less than the remanence. NdFeB is the highest practical permanent magnet material for Br found today.

2. The unit of magnetic induction coercive force (Hcb) is ampere/meter (A/m) and Oersted (Oe) or 1 Oe≈79.6A/m

When the magnet after technical saturation magnetization is reverse magnetized, the value of the reverse magnetic field strength required to reduce the magnetic induction intensity to zero is called the magnetic induction coercive force (Hcb). But at this time, the magnetization of the magnet is not zero, but the applied reverse magnetic field and the magnetization of the magnet cancel each other out. (The external magnetic induction is zero.) At this time, if the external magnetic field is cancelled, the magnet still has certain magnetic properties. The coercivity of neodymium iron boron is generally more than 11000 Oe.

3. The units of intrinsic coercivity (Hcj) are Ampere/meter (A/m) and Oersted (Oe) 1 Oe≈79.6A/m

The strength of the reverse magnetic field required to reduce the magnetization of the magnet to zero is called the intrinsic coercivity. The intrinsic coercive force is a physical quantity that measures the resistance to demagnetization of the magnet. If the applied magnetic field is equal to the intrinsic coercive force of the magnet, the magnetism of the magnet will be basically eliminated. The Hcj of NdFeB will decrease with the increase of temperature, so you should choose a high Hcj grade when you need to work in a high temperature environment.

4. The unit of magnetic energy product (BH) is focal/m3 (J/m3) or high•Ou (GOe) 1 MGOe≈7.96k J/m3

The product of B and H at any point on the demagnetization curve, BH, is called the magnetic energy product, and the maximum value of B×H is called the maximum magnetic energy product (BH)max. The magnetic energy product is one of the important parameters of the energy stored in a constant magnet. The larger the (BH)max, the greater the magnetic energy contained in the magnet. When designing the magnetic circuit, try to make the working point of the magnet near B and H corresponding to the maximum magnetic energy product.