Usually by 4 parameters the magnetic property of a magnet can be identified say.
Residual Magnetism (Br): the unit is Gs/mT, 1mT equals 10Gs;
Coersive force (Hcb): the unit is Oe;
Intrinsic coersive force (Hcj): the unit is Oe;
Maximum product energy (BHmax): the unit is MGOe;
Br, Hcj and BHmax are the most common description.
Relationships among Br, Hcj and BHmax:
Br usually reflects surface magnetic flux after the magnetization of a magnet;
Hcj reflects the ability of a magnet's anti-demagnetize and high temperature resistant;
BHmax is the maximum value of Br by Hcj, it directly reflects how strong is a magnet;
We never find a bonded ndfeb magnet with BHmax larger than 11.5MGOe;
Generally when BHmax value is fixed, when Br is higher the Hcj must be smaller, vice versa. It is incorrect to judge a magnet only by single value of BHmax, Br or Hcj, the most suitable parameter is the best one for a particular project.
Influence on magnetization
Universally known that under the same condition say. Same dimensions, same poles and same magnetization voltage, the higher of the BHmax the higher of surface gauss we got, however, when BHmax is the same, the following influence on magnetization by Br and Hcj will occur:
High Br value, low Hcj value: under the same voltage, we get higher surface gauss;
Low Br value, high Hcj value: in order to get the same surface gauss, we need higher magnetization voltage;
For multi-poles magnets, we need to make magnet powder with high value of Br and lowe value of Hcj, while for magnetic segment, we do high value of Hcj and Low value of Br, because the magnets have to undertake high demagnetization current and overload.