How to judge the magnetic performance of the connector with a strong magnet?
The performance of a general magnetic material can be expressed by its four parameters, namely residual magnetic induction (referred to as remanence) Br (unit Gauss Gs or millimeter mT, 1mT = 10Gs), coercivity Hcb (unit Oster Oe) , intrinsic coercivity Hcj (unit Oster Oe), maximum magnetic energy product (BH) max (units Mega Omega MGOe), of which Br, Hcj, (BH)max three parameters are the most direct representation.
The relationship between Br, Hcj, (BH)max
The size of Br can generally be considered to indicate the surface magnetic field after magnetization of the magnetic component; the size of Hcj can indicate the ability of anti-demagnetization and temperature resistance after magnetization; (BH)max is the maximum product of Br and Hcj. Its size directly indicates the performance of the magnet. At present, we have not detected a magnet with a bonded NdFeB(BH)max greater than 11.5.
In general, in magnets with similar (BH)max, Br is high and Hcj is low; Hcj is high and Br is low. We can't just determine the quality of the product by the level of (BH)max, but also whether the height of Br and Hcj is suitable for the products we need.
The effect of the size of the three on magnetization
It is well known that under the same conditions, that is, the same size, the same number of poles and the same magnetization voltage, the magnetic material obtained by the magnetic material with high magnetic energy product is also high, but at the same (BH)max value, Br and Hcj The height of the magnet has the following effects:
Br high, Hcj low: under the same magnetization voltage, can get higher surface magnetic;
Br is low, Hcj is high: to obtain the same surface magnetic, a higher magnetizing voltage is required;
Whether the size of the three indicates the quality of the material
We can't decide whether it is good or bad by the height of Br, Hcj, (BH)max. Strong magnet manufacturers determine the level of the three products according to their use and required characteristics; even under the condition of equivalent (BH)max value, Also depends on the use of the product, the requirements of magnetization to decide whether to use high Br value, low Hcj, or vice versa.
For multi-pole magnetization, it is necessary to use a magnetic powder with a high Br-Hcj low. For a magnetic tile, a strong magnet manufacturer generally uses a magnetic powder with a low Hcj high Br, which is because the motor used for the magnetic tile has to withstand a large degree in use. Magnetic current and overload.
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