Magnetic Terms
Energy product (WxH)max
The maximum energy product of the flux density B and field strength H is the most important quality of a magnetic material. The higher the energy product, the greater the magnetic energy. The higher the (WxH)max value of a magnetic material, the lower the magnetic volume required for a certain task with otherwise identical ratios.
Coercivity Hc
Coercivity is the field force necessary to eliminate magnetization. The higher the value, the more resistant the magnetiza- tion. A distinction is made between HcB and HcJ.
Remanence (Br)
Remanence is the residual magnetization of a magnetic material magnetized up to saturation in a closed circle. Remanence is stated in Gauss (G), Tesla (T) or Millitesla (mT).
Operating temperature
The operating temperature is the highest temperature to which a magnet can be exposed without suffering a permanent loss of its magnetic power. It is an approximate value because there is dependence to the dimensioning. There are factors, e.g. mechanical or chemical stress, which may further limit the maximum operating temperature.
Curie temperature
If the Curie temperature is reached, the magnetic material loses its magnetism.
Magnetic materials features table:
| Magnetic Materials | ||||||||
| Magnetic material | Energy- product | Remanence | Coercivity | Temperature- coefficient | Operation temperature | Curie- temperature | Density | |
| Br | ||||||||
| (B x H) max | mT | HCB | HCJ | per 1 °C | °C | °C | g/cm3 | |
| kJ/m3 | kA/m | kA/m | ||||||
| Barium ferrite | 7.2 – 7.6 | 210 – 220 | 130 – 135 | 220 | -0.20% | 250 | 450 | 4.9 |
| isotropic | ||||||||
| Barium ferrite | 28.9 – 29.5 | 390 – 400 | 145 – 160 | 150 – 165 | -0.20% | 250 | 450 | 4.9 |
| anisotropic | ||||||||
| Strontium ferrite | 24.5 – 25.5 | 350 – 370 | 210 – 245 | 220 – 255 | -0.20% | 250 | 450 | 4.9 |
| anisotropic | ||||||||
| AINiCo 500 | 35 – 36 | 1,120 – 1,160 | 47 – 49 | 47 – 49 | -0.02% | 400 | 890 | 7.3 |
| Samarium- | 140 – 150 | 850 – 890 | 620 – 670 | 1,100 – 1,200 | -0.04% | 250 | 720 | 8.3 |
| Cobalt SM 18 | ||||||||
| SmCo5 | ||||||||
| Samarium- | 190 – 205 | 1,000 – 1,050 | 680 – 750 | 1,195 – 1,500 | -0.03% | 250 | 800 | 8.3 |
| Cobalt SM24 | ||||||||
| Sm2Co17 | ||||||||
| Neodymium- | 260 – 285 | 1,180 – 1,220 | 860 – 915 | >= 955 | -0.13% | 80 | 310 | 7.4 |
| Iron-Boron | ||||||||
| NdFeB 35* | ||||||||
Values determined at a temperature of 20 °C.
*Qualities available with an operating temperature of up to 220 °C.
